Instrument Rating Checkride Study Guide

• Hold at least a private pilot certificate (or apply concurrently) with the appropriate airplane rating
• Read, speak, write, and understand English
• Receive and log ground training (or a home-study course) and an endorsement for the knowledge test; pass the knowledge test
• Receive and log flight training on the areas of operation and an endorsement for the practical test (61.65(a))

• 50 hours of cross-country time as PIC, of which 10 hours must be in an airplane
• 40 hours of actual or simulated instrument time in the areas of operation, of which 15 hours must come from an authorized instructor who holds an instrument-airplane rating
• 3 hours of instrument flight training in an airplane within 2 calendar months before the practical test (61.65(d))

One cross-country flight in an airplane with an authorized instructor, performed under IFR on a filed flight plan, that involves:

• A flight of 250 NM along airways or by directed ATC routing
• An instrument approach at each airport
• Three different kinds of approaches with the use of navigation systems (61.65(d))

With the instrument rating, you may:

• Fly in IMC on an IFR clearance
• Operate in Class A airspace — all operations there must be conducted under IFR (91.135)
• Fly Special VFR between sunset and sunrise — night SVFR requires an instrument-rated pilot and an aircraft equipped for instrument flight (91.157(b)(4))

Without it, you may not act as PIC under IFR or in weather conditions less than the minimums prescribed for VFR (61.3(e)). The limitation: the rating alone isn't enough — exercising it also requires 61.57(c) recent instrument experience, covered below.

Within the 6 calendar months preceding the month of the flight, you must have performed and logged — in actual conditions or simulated with a view-limiting device:

• Six instrument approaches
• Holding procedures and tasks
• Intercepting and tracking courses through the use of navigational electronic systems (61.57(c)(1))

You may not act as PIC under IFR or in weather less than VFR minimums until current again.

• Inside the six months after losing currency, you can regain it yourself: perform the 61.57(c) tasks in VMC with a safety pilot under simulated conditions, or in an approved simulator, FTD, or ATD.
• Once you've been non-current for more than six calendar months, the only way back is an instrument proficiency check (61.57(d)).

The IPC must include the areas of operation in the instrument ACS and be conducted in an aircraft of the appropriate category or a representative full flight simulator or FTD.

It may be given by:

• An examiner
• An authorized instructor (CFII — the typical route)
• A U.S. Armed Forces instrument-flight-test authority
• A company check pilot (121/125/135/91K)
• A person approved by the Administrator (61.57(d)(3))

Yes. The tasks may be flown in a full flight simulator, FTD, or ATD — alone or in any combination with an aircraft — provided the device represents the category of aircraft and the tasks are performed in simulated instrument conditions. Your logbook entry must record the device, time, and content of the session (61.51(g)(5)). No instructor is required by 61.57(c)(2) for currency in a device.

For simulated instrument flight:

• The other control seat is occupied by a safety pilot holding at least a private pilot certificate with category and class ratings appropriate to the aircraft
• The safety pilot has adequate vision forward and to each side (or a competent observer supplements it)
• The aircraft has fully functioning dual controls — with a narrow exception for a single throwover control wheel (91.109(c))

You (under the hood): PIC time as sole manipulator of an aircraft you're rated in (61.51(e)), plus instrument time — recording the location and type of each approach and the safety pilot's name (61.51(g)(3)).

The safety pilot: may log SIC time, since more than one pilot is required by the regulation the flight is conducted under (91.109(c)), provided they hold the appropriate category and class ratings, and an instrument rating if the flight requires one; a non-instrument-rated safety pilot can't log SIC on a flight conducted under IFR (61.51(f)(2)). If you agree the safety pilot is acting as PIC, they may instead log PIC for that time (61.51(e)(1)(iii)).

Only for flight time when you operate the aircraft solely by reference to instruments under actual or simulated instrument conditions. To count toward 61.57(c) currency, the entry must include the location and type of each approach and the safety pilot's name if one was required (61.51(g)).

Yes — BasicMed doesn't restrict IFR, so long as you hold the instrument rating and are current. The conditions and limitations:

• Aircraft authorized for not more than 7 occupants, flown with no more than 6 passengers, max takeoff weight 12,500 lb or less
• At or below 18,000 ft MSL — so no Class A — and 250 KIAS or less, within the U.S. unless authorized (61.113(i))
• Valid U.S. driver's license; held any FAA medical after July 14, 2006; online medical course every 24 calendar months; comprehensive medical examination by a state-licensed physician (documented on the CMEC checklist) every 48 calendar months (61.23(c)(3))

Currency is the legal floor: six approaches in six months, all of which you could have flown under the hood in clear, calm air. Proficiency is being able to hand-fly an approach to minimums, single-pilot, in turbulence, after a reroute. You can be perfectly legal and dangerously rusty — which is why the ACS calls out proficiency versus currency as a risk element (IR.I.A.R1) and why personal minimums exist.

Self-imposed limits more conservative than the regulations — your own ceiling/visibility floors, wind limits, and recency requirements. If the weather is below your personal minimums, delay or cancel; the IFH's planning scenario treats that as the baseline good decision (IFH ch. 10). Raise them when anything is unfamiliar: a new-to-you aircraft, different avionics or flight display systems, or a long gap since your last approach in actual (IR.I.A.R2, R4).

• Full flight simulator or FTD: up to 30 hours if completed under a part 142 training center program, otherwise up to 20 hours
• Aviation training devices: up to 10 hours in a basic ATD or up to 20 hours in an advanced ATD (FAA-approved, with an authorized instructor providing the time)
• Except for the part 142 case, no more than 20 total hours of device time may be credited, in any combination (61.65(h), (i), (j))

Everything that degrades an instrument scan degrades it faster in IMC: fatigue, stress, illness, medication, and hypoxia. The stakes are higher because instrument flight removes the natural horizon — the vestibular illusions that cause spatial disorientation (the leans, graveyard spiral, and friends) are only overcome by a disciplined scan and trust in the instruments, both of which erode when you're tired or impaired (IFH ch. 3). If you wouldn't be sharp enough to hand-fly an approach to minimums today, the answer is no-go.

Because instrument flying is procedural, and the procedures live in the equipment. A different autopilot, GPS navigator, or PFD changes how you load an approach, sequence a missed, or recognize a failure — at exactly the moment your attention is fully committed. Mitigate it:

• Get transition training before flying IFR with new equipment
• Rehearse the button-flows on the ground
• Raise your personal minimums until the avionics are second nature

Flight Service (phone or 1800wxbrief.com) and automated resources like aviationweather.gov — a self-briefing per AC 91-92 is regulatory compliant. Three briefing types:

• Standard — the full package for a flight you haven't briefed yet
• Abbreviated — to update specific items or supplement earlier data
• Outlook — when departure is 6 or more hours away; planning only, follow up with a standard briefing before departure

METAR: the routine report, issued hourly.

SPECI: a special, off-schedule report triggered by significant changes — for example a thunderstorm beginning or ending, or a cloud layer appearing below 1,000 ft that wasn't in the previous report.

Both are surface observations from automated systems, with human augmentation at some larger airports (AIM 7-1-2, TBL 7-1-1).

A Terminal Aerodrome Forecast — a concise statement of expected conditions at an airport for a specified period, using METAR code. Scheduled four times daily at 0000Z, 0600Z, 1200Z, and 1800Z; most locations get a 24-hour forecast period, some get 30 hours. Amended as required — always check the date-time group: FM100000 is 0000Z on the 10th, not 1000Z (AIM 7-1-28).

UA is a routine pilot report; UUA is urgent. Facilities are required to solicit PIREPs when reported or forecast:

• Ceilings at or below 5,000 ft, or visibility at or below 5 miles
• Thunderstorms, or icing of light degree or greater
• Turbulence of moderate degree or greater, wind shear, or volcanic ash

Heights in PIREPs are MSL. Give them freely — they're the best real-time truth about ice and turbulence.

AIRMETs cover en route weather hazardous at intensities below SIGMET criteria:

• Sierra — IFR conditions and extensive mountain obscuration
• Tango — moderate turbulence, sustained surface winds of 30 knots or greater, and nonconvective low-level wind shear
• Zulu — moderate icing and freezing level heights

Over the contiguous U.S. they're graphical, valid at discrete times up to 12 hours out (AIM 7-1-6).

Non-convective weather affecting the safety of all aircraft:

• Severe icing not associated with thunderstorms
• Severe or extreme turbulence or clear air turbulence (CAT) not associated with thunderstorms
• Dust storms or sandstorms lowering surface visibility below 3 miles
• Volcanic ash

Unscheduled; valid 4 hours — except 6 hours for SIGMETs associated with tropical cyclones or volcanic ash clouds (AIM 7-1-6).

Issued for any of:

• Severe thunderstorms: surface winds 50 knots or greater, or hail at the surface 3/4 inch or greater, or tornadoes
• Embedded thunderstorms
• A line of thunderstorms
• Heavy precipitation affecting 40 percent or more of an area of at least 3,000 square miles

Bulletins are issued hourly at H+55, forecast valid up to 1 hour. Any Convective SIGMET implies severe or greater turbulence, severe icing, and low-level wind shear (AIM 7-1-6).

The GFA (aviationweather.gov/gfa) replaced the legacy text area forecast: an interactive display of observations, forecasts, and warnings viewable from 14 hours in the past to 15 hours in the future — thunderstorms, clouds, flight category, precipitation, icing, turbulence, and wind. Icing, turbulence, and wind are forecast in 3,000-ft increments up to 30,000 ft MSL. Static Aviation Cloud/Surface Forecast images are updated every 3 hours with snapshots at 3–18 hours (AIM 7-1-4).

Each station line gives forecast wind and temperature at standard altitudes: direction in tens of degrees true, speed in knots, then temperature in Celsius — 2615+12 means 260° true at 15 knots, +12 °C. Heights are MSL, and briefers interpolate between levels and stations for your cruising altitude (AIM 7-1-5). Every FB carries the reminder "TEMPS NEG ABV 24000" — above 24,000 ft the sign is dropped because temperatures are always negative.

The Storm Prediction Center's forecast of general and severe thunderstorm areas: Day 1, Day 2, and Day 3 outlooks plus a combined Day 4–8 severe weather outlook. Categorical risks, in ascending order: TSTM (general thunderstorms), MRGL, SLGT, ENH, MDT, HIGH (SPC). For IFR planning it's your earliest look at whether convection will own your route.

The surface analysis chart shows where the pressure systems and fronts are — the IFH's planning scenario uses it, along with depictions of IFR-condition areas, to find where conditions are improving and where a diversion to VFR weather could go (IFH ch. 10). Ceiling and visibility products depict the standard flight categories (AIM 7-1-7):

• LIFR — ceiling below 500 ft and/or visibility below 1 SM
• IFR — 500 to below 1,000 ft and/or 1 to below 3 SM
• MVFR — 1,000 to 3,000 ft and/or 3 to 5 SM
• VFR — ceiling greater than 3,000 ft and visibility greater than 5 SM

The big limitation: data-linked NEXRAD mosaic imagery shows where the weather was, not where it is — it can be 15 to 20 minutes older than the age indication on the display, so use it strategically to route around weather, never tactically to pick through cells. FIS-B itself is a free broadcast over the 978 MHz UAT ADS-B network — line-of-sight to ground stations, with products like METARs, TAFs, AIRMETs/SIGMETs, and NEXRAD at defined update and look-ahead ranges (AIM 7-1-9).

Ice forms when supercooled visible moisture strikes the airframe at 0 °C or colder — clear ice near freezing, rime at colder temperatures, mixed in between (the ice types, their aerodynamic effects, and the in-flight escape drill are covered under Task II.A). The weather briefing is where the encounter is won:

• Find the freezing level from AIRMET Zulu and the GFA icing forecasts, and match it against your route altitudes (AIM 7-1-4, 7-1-6)
• Keep an out along the route — an altitude warmer than freezing, or air below the cloud bases
• PIREPs are the best real-time truth about where the ice actually is — give them and get them

A thunderstorm packs nearly every aviation hazard into one bundle — turbulence, hail, lightning, icing, updrafts and downdrafts.

• Circumnavigate strong cells by at least 20 miles; echoes separated by 20–30 miles may still hide severe turbulence
• Overflying: clear the top by 1,000 ft for every 10 knots of wind at that level
• Never fly under a thunderstorm
• Tops above 35,000 ft — extremely hazardous; embedded storms in large cloud masses are the IMC trap
• Radar shows precipitation, not turbulence; lightning risk peaks between –5 °C and +5 °C

Wind shear is dangerous because of the killer sequence: a headwind shear followed by a tailwind/downdraft — you've already pulled power and lowered the nose, leaving you nose-low and power-low near the ground. It's a change in wind speed and/or direction over a short distance, worst near thunderstorms and low-level temperature inversions: a tailwind shearing to a headwind balloons you above glidepath, and a headwind shearing to a tailwind drops you below it. Some airports have LLWAS alerts, and the answer to shear indications early on approach is a prompt missed approach, because recovery at low altitude may be impossible.

Fog needs air cooled to saturation or moisture added to it — expect it when the temperature/dewpoint spread is 5° or less and closing. The classic setup: arriving near dusk with falling temperatures. When fog is in play, plan extra fuel and solid alternates, and track trends en route via ATIS/ASOS/AWOS updates.

Heat exchange with the surface sets the character:

Warmed from below: convective currents make the mass unstable — cumulus clouds, showers, turbulence, but good surface visibility.

Cooled from below: the mass turns stable — low stratus clouds and fog, smooth air, and poor surface visibility, because smoke, dust, and haze stay trapped near the surface (PHAK ch. 12).

Add moisture and the pattern becomes your forecast: moist and stable means widespread low ceilings; moist and unstable means convection. Frontal and forecast products only tell you where these air masses are headed.

Warm front: moves slowly (10–25 mph) as warm air slides up over the retreating cold air — expect cirriform then stratiform clouds and fog in a wide band ahead of the boundary, a broad shield of low IFR ceilings, with thunderstorms possible in summer.

Cold front: faster (25–30 mph); the dense air plows under the warm mass like a snowplow, so the weather band is narrow and intense — towering cumulus and cumulonimbus, rain showers, gusty variable winds, and a fast-moving cold front can push a squall line ahead of it, then clear rapidly behind (PHAK ch. 12).

Clouds are classified by base height:

• Low (up to 6,500 ft AGL — stratus, stratocumulus, nimbostratus): carry the ceiling and icing threats from supercooled droplets
• Middle: can hold moderate icing
• High: ice crystals, pose no icing threat

Towering cumulus and cumulonimbus mean instability, turbulence, and thunderstorms — including embedded ones hidden in other layers (PHAK ch. 12).

Frost deposits on cool, clear, calm nights when the surface cools below a below-freezing dew point. It disrupts airflow and can drastically reduce lift — remove it all before flight (effects detailed under Task I.C).

Divert while it's still easy:

• Destination weather trending below your personal minimums — or below approach minimums — while an alternate holds solid conditions (the IFH scenario keeps an MVFR alternate in its hip pocket the whole flight, IFH ch. 10)
• PIREPs of icing at your altitudes with a falling freezing level
• Convective SIGMETs filling in across the route
• Anything that erodes your 91.167 fuel reserve — holding, reroutes, stronger headwinds

The decision rule: if weather is below personal minimums, delaying or diverting is the good decision, not the failure (IFH ch. 10).

Apply the 1-2-3 rule: no alternate is required only if the destination has a published instrument approach (part 97 or special), and from 1 hour before to 1 hour after your ETA, forecasts show ceiling at least 2,000 ft above the airport elevation and visibility at least 3 SM (91.169(b)). Otherwise file an alternate — and carry the fuel to reach it (91.167). Whether a given airport can legally be your alternate (600-2 / 800-2 and friends) is covered under Task I.C.

• IFR en route low-altitude charts — the instrument equivalent of the sectional, revised every 56 days (IFH ch. 1)
• Preferred routes, listed in the Chart Supplement for major terminal and en route environments — filing them means fewer route changes (IFH ch. 10)
• Tower en route control (TEC) — tower-to-tower routing beneath the en route structure between nearby terminal areas (IPH ch. 2)
• Chart Supplement for airport data, VOR receiver checkpoints, FSS and ARTCC frequencies, and special notices (IFH ch. 10)
• NOTAMs and the Terminal Procedures Publication for the procedures at each end

Check the en route chart for SUA along your route:

• Prohibited areas — flight is prohibited; a Federal airway never includes prohibited-area airspace
• Restricted areas — if the area is not active and released to the FAA, ATC lets your IFR clearance operate through it without a specific clearance to do so; if it's active, ATC issues a clearance that keeps you out
• MOAs — nonparticipating IFR traffic is cleared through only if ATC can provide IFR separation from the military activity; otherwise expect a reroute or restriction (IFH ch. 1)

TFRs pop up by NOTAM — one more reason to re-brief NOTAMs close to departure.

• Minimum en route altitude (MEA) — guarantees nav signal reception and obstacle clearance (typically 1,000 ft, 2,000 ft in designated mountainous areas)
• Minimum obstruction clearance altitude (MOCA) (charted with an asterisk, *3400) — same obstacle clearance, but nav signal assured only within 22 NM of the VOR; you may fly it below the MEA when within 22 NM (91.177(a)(1))

The rest of the charted-minimums alphabet — MRA, MCA, MAA, OROCA — is decoded under Task V.B.

Except for takeoff and landing: 1,000 ft above the highest obstacle within 4 NM of the course — 2,000 ft in designated mountainous areas (91.177(a)(2)). Climb to a higher minimum altitude begins immediately after passing the point where it applies, except an intervening obstruction means crossing the fix at or above the MCA (91.177(b)).

• In controlled airspace: whatever ATC assigned — the odd/even rule doesn't apply to you (unless cleared "VFR-on-top," in which case fly the VFR cruising altitudes of 91.159)
• In uncontrolled airspace below 18,000 ft MSL: magnetic course 0–179° — odd thousands; 180–359° — even thousands (91.179)

At cabin pressure altitudes:

• Above 12,500 ft MSL up to and including 14,000 ft — required minimum flight crew uses oxygen for the portion of flight at those altitudes over 30 minutes
• Above 14,000 ft — required crew uses oxygen the entire time
• Above 15,000 ft — every occupant must be provided oxygen (91.211(a))

Considering weather reports, forecasts, and conditions — enough to:

1. Fly to the first airport of intended landing,
2. Fly from there to the alternate (unless the 1-2-3 exception applies), and
3. Fly after that for 45 minutes at normal cruising speed (91.167)

The 45 minutes is a planning floor, not a comfort level — headwinds, holds, and reroutes eat it fast.

At the ETA at the alternate, ceiling and visibility at or above:

• Precision approach: 600-2 — 600 ft ceiling and 2 SM
• Nonprecision approach: 800-2

…unless the airport has nonstandard alternate minimums published in the TPP — flagged by a triangle-A on the approach chart; A-NA means the airport can't be filed as an alternate at all (often an unmonitored NAVAID or no weather reporting) (IPH ch. 1). If the airport has no instrument approach, the forecast must allow descent from the MEA, approach, and landing under basic VFR (91.169(c)(2)).

Depends on your receiver:

• TSO-C129/C196 (non-WAAS): an airport with only GPS approaches can't be used as the alternate unless the specific AIM requirements are met — you can't plan GPS at both destination and alternate
• WAAS (TSO-C145/C146): may plan an RNAV (GPS) approach at the alternate where authorized

And GPS is not a substitute for the DME or ADF required by a conventional approach at the alternate — you need the actual equipment on board (IPH ch. 1).

You must have filed an IFR flight plan and received an ATC clearance (91.173). The plan contains the information required by 91.153(a) — aircraft, equipment, route, altitude, times, fuel, souls — plus an alternate airport unless the 1-2-3 exception applies (91.169(a)). File at least 30 minutes prior to expected departure clearance; you can also file airborne with FSS or directly with ARTCC, workload permitting (IFH ch. 10).

Upon canceling or completing the flight, notify FSS or ATC (91.169(d)).

• Towered destination: canceled automatically on landing
• Non-towered destination: canceling is your job — by radio before landing or by phone after
• Airborne cancellation: allowed any time you're in VFR conditions outside Class A — "cancel my IFR flight plan" — but be certain the rest of the flight stays VFR; separation services end immediately (IFH ch. 10)

NOTAMs can eliminate options your plan assumed were available — a NOTAM'd out-of-service localizer removes an approach from consideration, and a closed runway changes both the departure and the performance math (IFH ch. 10). Preflight action for any IFR flight includes all available information, NOTAMs prominently (91.103).

Check:

• FDC NOTAMs for procedure changes
• Field NOTAMs for runway/taxiway closures and lighting
• The TPP's inoperative-components table for raised minimums
• Re-check just before departure

Layer the constraints:

1. Legal floor — MEA/MOCA on airways, 91.177 off them, then the odd/even scheme for direction of flight (91.179)
2. Weather — freezing level and forecast icing (AIRMET Zulu, GFA); cloud tops if you can get on top; winds aloft from the FB for groundspeed
3. Terrain and glide — in a single, altitude is your engine-out option budget over mountains and at night
4. Physiology — the 91.211 oxygen thresholds
5. Performance — the POH true airspeed and fuel flow for the altitude actually attainable at your weight (IFH ch. 10)

Sum each leg's time — leg distance ÷ groundspeed (POH TAS corrected for the FB winds aloft) — plus the climb and descent segments, then add the total time en route to your departure time.

Everything you file runs on Coordinated Universal Time (UTC — "Zulu"). Converting from standard time, add:

• Eastern: 5 hours
• Central: 6 hours
• Mountain: 7 hours
• Pacific: 8 hours

For daylight time, subtract 1 hour from the correction (AIM 4-2-12, TBL 4-2-12). So a 2:45 p.m. CDT departure is 1445 + 5 = 1945Z, and a 1:30 time en route makes the ETA 2115Z.

Recompute from what's actually in the tanks, not the plan:

1. Current fuel on board ÷ current burn = endurance remaining
2. Subtract the hold to the EFC, then fuel to fly the approach, then fuel to the alternate, then the 45-minute reserve (91.167)
3. If the answer goes negative before the reserve does, the decision is made: tell ATC and divert now, while the alternate is still reachable with reserves intact

The point of planning-phase fuel discipline is that in the air this becomes arithmetic, not judgment under pressure.

Ice alters the airfoil shape in three ways:

• Maximum lift can drop 30 percent or more
• Drag can rise 100 percent or more
• The wing stalls at a lower angle of attack

So ice that had little effect in cruise can stall the wing as you slow and increase AOA for approach and landing — which is why any accumulation of ice or frost must be removed before flight (IFH ch. 4). The full aerodynamic picture — horn ice, tailplane icing, roll upset — is covered under Task II.A.

• Pre-takeoff: remove any accumulation of ice or frost before attempting flight — with contamination aboard, the aircraft may not become airborne at all (IFH ch. 4)
• In cruise: act before it builds — leave visible moisture (climb, descend, or turn) or reach above-freezing air; report to ATC and request new routing or altitude; watch small protrusions as your "ice evidence probe," they accrete first
• On approach: anticipate the stall at a lower-than-normal AOA with contaminated surfaces — configuration and speed changes deserve wide margins, and diverting to better weather beats an approach flown with ice aboard (IFH ch. 4, ch. 10)

ATC: separation comes with an IFR clearance in controlled airspace — in uncontrolled airspace no one is sequencing you, radar and radio coverage have floors (the reason void times exist), and controller workload can mean delayed clearances or reroutes (IFH ch. 10). ATC also can't see your ice or feel your turbulence — you have to tell them.

Planning apps: an autorouted plan is only as good as its database currency and the forecast it ingested. Verify chart and database cycles, sanity-check the route against preferred routes and NOTAMs, and be able to defend every altitude and fuel figure yourself — the ACS allows a computer-generated plan, but the explanation is all you.

Anti-ice prevents ice from accumulating in the first place — you turn it on before entering icing conditions. Pitot heat, heated props, and windshield heat are anti-ice.

Deice removes ice after it has formed — pneumatic boots are the classic example, cycled once ice has accreted (IFH glossary).

• Clear (glaze) — glossy, transparent, formed by the relatively slow freezing of supercooled water. Favored by temperatures near freezing, large droplets, high liquid water content, and higher speeds. Dense and hard; large accretions can form horns.
• Rime — rough, milky, opaque; instantaneous freezing traps air pockets, so it's porous and brittle. Favored by low temperatures, small droplets, low speeds.
• Mixed — clear and rime together on the same surface. Shape and roughness matter more aerodynamically than type (IFH ch. 4).

When flying in visible moisture — rain or cloud droplets — with the outside air temperature between about +2 °C and –10 °C (IFH ch. 11). Monitor the OAT anytime you're in visible moisture. Small or narrow objects collect ice first, which is why a wing strut or other small protuberance works as an "ice evidence probe" — and why the tailplane, thinner than the wing, is a better ice collector than the surface you can see (IFH ch. 4).

It reshapes the airfoil:

• Max lift coefficient down — a 30 percent reduction is not unusual; large horn accretions can cost 40–50 percent (IFH ch. 4)
• Drag up 100 percent or more — 200 percent or higher with horns
• The wing stalls at a lower angle of attack and higher speed — ice that was benign in cruise can bite when you slow and pitch up on approach
• As little as one-half inch of leading-edge ice can cut lifting power by 50 percent on some aircraft (IFH ch. 11)
• Severe icing can trigger roll upset — airflow separation self-deflects the ailerons (IFH ch. 4)

• Trace — ice perceptible; accumulation slightly exceeds sublimation; equipment not needed unless the exposure exceeds about an hour
• Light — a problem only if prolonged (over 1 hour); occasional use of equipment removes or prevents it
• Moderate — even short encounters are potentially hazardous; use equipment or divert
• Severe — equipment fails to reduce or control the hazard; immediate diversion is necessary (IFH ch. 11)

Induction icing chokes off air to the engine rather than lift from the wing. The classic form is carburetor ice: moist air cooling through the venturi can form ice on the venturi walls and throttle plate at ambient temperatures between 20 °F and 70 °F (–7 °C to 21 °C) — no visible moisture required. The remedy is carburetor heat, which routes exhaust-heated air to melt the ice (IFH ch. 4). Fuel-injected engines use an alternate air source for a blocked intake.

Two immediate options: leave the area of precipitation or change altitude to above-freezing air — and remember the warmer air may be above you, which is why you noted the freezing level in preflight. If neither works, plan an immediate landing at the nearest suitable airport. Report the icing to ATC — aircraft type plus intensity — and request new routing or altitude (IFH ch. 11).

No. A FIKI airplane is safe only in the conditions evaluated during certification — and no aircraft is evaluated for every condition. Severe icing is outside the certification envelope by definition, and supercooled large drops (SLD) — droplets larger than 50 microns, found in and below clouds — are conditions no aircraft is certificated for. Ice protection equipment "gives a pilot more time to get out of the icing conditions" — it is not designed for indefinite exposure (IFH ch. 4, ch. 11).

• Pitot tube and static ports — the pressure instruments start lying, a serious hazard in IMC (failure modes covered under Task II.B)
• Stall warning systems — the vane or switch can freeze, and even a working warning may be useless because the iced wing stalls at a lower AOA than the system expects
• Windshield — you may break out at minimums unable to see forward
• Antennas — small and unprotected, they ice quickly, vibrate, distort signals, and can break off
• Propeller — ice on the blades costs thrust like ice on a wing costs lift (IFH ch. 4)

• Airframe (wings, empennage leading edges) — rubber pneumatic boots, inflated by vacuum/pressure pump discharge air; an oil separator keeps pump oil from deteriorating the rubber (IFH ch. 5). Boots are deice: cycle them after accretion.
• Propeller — normally anti-iced rather than deiced, so ice is never shed into the engine or airframe (IFH ch. 4)
• Windshield — an electrically heated plate giving a band of clear vision, or a spray bar feeding deicing fluid (IFH ch. 4)
• Pitot tube — electric heat; verify preflight with the ammeter or the POH method (IFH ch. 5)
• Intake/fuel — carburetor heat or alternate air for induction ice (IFH ch. 4); follow the POH for fuel-system provisions

Extending flaps (or increasing speed) increases the tailplane's negative angle of attack — the tail's job is to push down, balancing the nose-down moment of a CG ahead of the center of pressure. With ice on the tail, that added push can exceed the contaminated tail's reduced stall margin: the tail stalls, the downforce vanishes, and the nose pitches down, classically just after selecting full or partial flaps on approach (IFH ch. 4).

Symptoms:

• Elevator control pulsing, oscillations, or vibration
• Abnormal nose-down trim change
• Reduced or lost elevator effectiveness
• Sudden uncommanded nose-down pitch (IFH ch. 4)

Recovery — nearly the opposite of a wing stall:

• Immediately retract flaps to the previous setting and apply nose-up elevator
• Increase airspeed appropriately for the reduced flap setting
• Apply power for configuration and conditions — but note high power can aggravate the condition in some designs; follow the manufacturer
• Make nose-down pitch changes slowly
• If boots are installed, cycle them several times

A tailplane stall can occur below VFE, and the condition worsens with speed at the same flap setting (IFH ch. 4).

Ice can partially block or limit control surfaces, making control movements ineffective, and severe icing can cause roll upset — airflow separation ahead of the ailerons induces self-deflection and degraded roll handling, possibly without the usual accumulation cues or a perceived stall (IFH ch. 4). That's why FIKI aircraft POHs publish minimum speeds for icing conditions, and why your preflight controls-free-and-correct check and a look at hinge lines and gaps for contamination matter more before an IFR departure.

Most GA autopilots control two axes — roll and pitch. They come in two sensing designs: position-based, where an attitude gyro senses displacement from a reference (wings level, a pitch attitude, a heading), and rate-based, where the turn-and-bank sensor feeds rate information (position change over time) — the S-TEC line is the classic rate-based example (IFH ch. 5). A flight director computes and displays the same steering commands on the attitude indicator for you (or the coupled autopilot) to follow. Know which type you have, every mode you'll use, and every way to disconnect it — from the POH/AFM, not folklore.

• Severe turbulence or an inadvertent thunderstorm encounter — disengage altitude-hold and speed-hold modes; chasing altitude and speed increases maneuvering and structural stress. Fly attitude and accept altitude/airspeed excursions (IFH ch. 11)
• When you've stopped monitoring it — over-reliance turns the automation from a supplementary aid into your only source of control, and a mode confusion or servo failure then goes unnoticed (IFH ch. 11)
• When hand-flying proficiency is the thing eroding — currency on the gauges is part of your risk management

Use it deliberately: brief the modes, verify each annunciation, and stay ready to hand-fly.

Three instruments, two pressures:

• Airspeed indicator — the only one using both pitot (ram) and static pressure; it displays the difference
• Altimeter — static only
• VSI — static only, displaying rate of change

The pitot tube (or the air data computer it feeds in glass installations) senses ram air; static pressure comes from flush ports positioned in undisturbed airflow (IFH ch. 5).

• Ram opening blocked, drain hole open — static pressure equalizes on both sides of the ASI diaphragm and the indicated airspeed slowly drops to zero
• Ram opening and drain hole both blocked — pressure is trapped, and the ASI acts like an altimeter: reading rises in a climb, falls in a descent — dangerously intuitive backwards

Only the ASI is affected; altimeter and VSI keep working. Prevention is the preflight (cover off, opening clear) plus pitot heat in visible moisture (IFH ch. 5).

• Altimeter — freezes at the altitude where the blockage occurred
• VSI — continuous zero indication
• ASI — keeps working but lies: above the blockage altitude it reads lower than actual (trapped static pressure is too high); below it reads faster than actual

The fix is the alternate static source, normally plumbed to the flight deck (IFH ch. 5).

Cabin pressure is slightly lower than outside static due to the venturi effect of air flowing around the fuselage, so:

• Altimeter indicates slightly higher than actual
• ASI indicates greater than actual airspeed
• VSI shows a momentary climb, then stabilizes

Check the POH/AFM for correction values, and verify on preflight that the valve opens and closes fully (IFH ch. 5).

Deliberate redundancy: manufacturers power the gyros from separate electrical and pneumatic sources so no single failure takes out your whole attitude reference. The classic arrangement is attitude and heading indicators on the vacuum system with an electric turn coordinator — or the reverse. The attitude instruments need roughly 4 inches Hg of suction; a turn-and-slip needs only about 2. Some instruments label their power source on the dial, but the POH/AFM is the authority — know which instrument survives which failure before the failure (IFH ch. 5).

Recognition: the gyros don't fail flag — the suction gauge is the direct clue, but the AI and heading indicator spin down gradually and drift, inviting you to follow them. Catch it with a disciplined cross-check: the AI disagrees with the turn coordinator, altimeter, and ASI trends.

What's left: the electric turn coordinator, pitot-static instruments, and compass — partial panel.

This is why the instrument flight deck check verifies the suction reading and why glass aircraft carry standby instruments (IFH ch. 5).

The compass card's center of gravity sits below its pivot, so magnetic dip drags it during turns:

• Turning through north — the card leads in the turn's direction, showing a false turn; roll out early (undershoot)
• Turning through south — the card lags; let it pass the desired heading (overshoot)

Rule of thumb: stop the turn 15° plus half your latitude before (north) or after (south) the target — at 40° latitude, 35° of anticipation. Errors grow with proximity to the poles (IFH ch. 5).

ANDS — accelerate north, decelerate south. On easterly or westerly headings, the pendulous card tilts with speed changes and magnetic dip converts the tilt into a false indication: acceleration shows an apparent turn toward north, deceleration toward south. Add oscillation error — the card swinging around the heading — and the lesson is to read the compass only in straight, level, unaccelerated flight, using the average of the swings when setting the heading indicator (IFH ch. 5).

• AHRS (attitude and heading reference system) — solid-state replacement for the attitude, heading, and rate gyros; it feeds attitude and heading to the primary flight display (PFD)
• ADC (air data computer) — takes pitot, static, and temperature inputs and computes altitude, IAS, TAS, and air temperature, output digitally to systems like the EFIS, autopilot, pressurization, and FMS

One box's failure takes out its whole family of indications at once — which is why you learn the failure annunciations and the standby instruments (IFH ch. 5).

Not a navigation system itself — a computer that manages the onboard navigation systems (IFH ch. 9). It carries a database of NAVAIDs, airways, intersections, DPs, STARs, and approaches plus aircraft performance data; you build and edit the flight plan through a control display unit (CDU) instead of managing each sensor separately. The FMS blends all available sensors (GPS, VOR, DME, etc.) into a best computed position — auto-tuning DME stations, it can fix position nearly as accurately as GPS — and modern units add VNAV to the lateral flight plan, providing guidance through departures, arrivals, and approaches (IFH ch. 5, ch. 9).

The system reverts to a composite (reversionary) mode — the surviving display (typically the multi-function display, MFD) presents the primary flight instruments. You lose real estate (the moving map page, airport data access), not the data itself. If the failure is deeper — AHRS, ADC, or total display loss — you're on the standby attitude indicator, altimeter, ASI, and magnetic compass installed for exactly this case. Practice the reversionary switch and the standby scan before you need them in IMC (IFH ch. 11).

It's an emergency — unlike round-dial aircraft, where alternator failure was just an abnormality, a technically advanced airplane's AHRS, ADC, and displays all feed on electrons (IFH ch. 11). Expect roughly 30–40 minutes of main battery — an approximation, never a guarantee — and land at the nearest suitable airport; at no time should you consider continuing the flight once the charging system has failed. The load-shed drill, standby battery, and essential bus are covered under Task VII.D.

Broadly the same airspace (91.215, 91.225):

• Class A, B, and C
• Within 30 NM of a listed Class B primary airport (the Mode C veil), surface to 10,000 ft MSL
• Above the ceiling and within the lateral limits of Class B or C, up to 10,000 ft MSL
• At and above 10,000 ft MSL, excluding at and below 2,500 ft AGL (for ADS-B this is Class E airspace)

Two differences: a transponder is also required from the surface to 10,000 ft MSL within 10 NM of certain listed (appendix D, section 2) airports (91.215(b)(5)(ii)); ADS-B is also required in Class E at and above 3,000 ft MSL over the Gulf of Mexico out to 12 NM from the coastline (91.225(d)(5)).

The transponder replies with Mode A codes and Mode C pressure altitude in 100-ft increments; ADS-B Out must be in transmit at all times once installed, and the transponder must be on in all controlled airspace (91.215(c), 91.225(f)).

Three signal families feed the panel (IFH ch. 9):

• Localizer — lateral guidance on 108.10–111.95 MHz, odd tenths; identified by a three-letter ident prefixed with "I" (e.g., I-SGF)
• Glideslope — vertical guidance, radiated on the front course only
• Marker beacons on 75 MHz — or DME/compass locators substituting — for range along the approach

Course width, glideslope geometry, and the marker light/tone indications are covered in depth under Task VI.B.

IFR GPS must:

• Meet TSO-C129 (or later equivalent standards) — WAAS units under TSO-C145a/C146a
• Be installed per airworthiness requirements and approved for that IFR operation
• Be operated per the POH/AFM or flight manual supplement
• Carry a current, updatable database supporting the operation (en route, terminal, approach)

Equipment approved under TSO-C115a, VFR GPS, and hand-held units meet none of that: they are not authorized for IFR navigation or approaches and count only as situational-awareness aids (IFH ch. 9).

Receiver autonomous integrity monitoring — the receiver's self-check that no satellite is feeding it corrupted data. Without RAIM you have no assurance the GPS position is accurate, which is why integrity monitoring is part of what makes an installation IFR-approved (IFH ch. 9). Satellite counts, RAIM predictions, and the in-flight RAIM messages are covered under Task V.A.

Surveyed wide-area ground reference stations monitor GPS signals; a master station computes corrections that a geostationary satellite broadcasts on the GPS frequency. Results:

• Accuracy — differential corrections shrink position error
• Integrity — real-time monitoring of the constellation
• Availability — the GEO acts as an additional ranging satellite

The payoff for you: an electronic glidepath independent of ground equipment or baro-aiding, immune to cold-temperature and altimeter-setting errors — the basis of LPV-style vertically guided approaches. Avionics are certified under TSO-C145a (sensor) or TSO-C146a (stand-alone) (IFH ch. 9).

Yes — GPS certified for IFR en route and terminal operations may substitute for ADF and DME, and it's also how the DME requirement at and above FL 240 gets met (91.205(e); IFH ch. 9). The conditions — current database, integrity monitoring, CDI sensitivity, and the final-approach limitation — are covered under Task V.A.

Electronic navigation databases update on a 28-day cycle; en route charts revise every 56 days (IFH ch. 1). An updatable database that supports the operation is required for IFR GPS, and GPS-for-DME/ADF substitution explicitly requires the database be current (IFH ch. 9). The confirmation step lives in your flight deck check (Task II.C) — and the risk item is quietly flying procedures that changed at the last cycle: moved waypoints, amended courses, changed minimums.

The governing guidance is AC 91-78 (per the ACS references). Treat the tablet like any other single point of failure:

• Currency — charts and databases downloaded and up to date before the flight
• Power — charged, with a backup power source or second device (or paper) reachable in flight
• Reliability — a locked-up or overheated device in IMC is a lost chart source; know how you'd continue
• Heads-down risk — program and brief on the ground

The IFH's broader warning applies: when the electronic source becomes your only source, its failure compromises your decision-making — plan the degraded case (IFH ch. 11).

Because before any flight involving aircraft control by instrument reference, you must check all instruments and their sources of power for proper operation (IFH ch. 5). It's a small slice of preflight time, but it's your only chance to catch a lazy gyro, a mis-reading altimeter, or a lapsed inspection before the airplane is your only horizon. The task is really two checks: the paperwork (is this airplane legally IFR-airworthy today?) and the instruments themselves (are they actually working?).

Everything from day VFR (the ATOMATOFLAMES list you know from the private), plus night VFR equipment if the flight is at night, plus the GRABCARD items — generator/alternator, two-way radio and navigation equipment suitable for the route, sensitive altimeter, slip-skid indicator, clock with seconds, attitude indicator, rate-of-turn indicator, and directional gyro (91.205(d)). Note "suitable for the route" is doing real work: the required nav equipment depends on what you filed.

On top of the annual (and 100-hour, if the aircraft is operated for hire) you already track:

• VOR check — every 30 days if using VOR for IFR navigation (91.171)
• Altimeter and static system test — within the preceding 24 calendar months (91.411; IFH ch. 5, ch. 10)
• Transponder test — within the preceding 24 calendar months (91.413; IFH ch. 10) — strictly this one isn't IFR-specific: it applies to any use of the transponder, VFR or IFR (91.215(c))

The altimeter/static and transponder tests live in the maintenance records; the VOR check lives in the aircraft log "or other record" you keep (91.171(d)).

The methods are in preference order: use a test signal or surface checkpoint if available before resorting to airborne checks (91.171(b)–(c)).

The person making the check enters date, place, bearing error and signs the aircraft log or other record. If a repair station's radiated test signal was used, the repair station also makes an entry certifying the transmitted bearing and date (91.171(d)). Four items — the examiner loves asking for all four.

1. Tune the VOT frequency — published in the Chart Supplement — and listen for the series of dots or the continuous 1020-Hz tone
2. Course selector to 0° — CDI centers with a FROM indication
3. Course selector to 180° — CDI centers with a TO indication

("Cessna 182": 0-FROM, 180-TO.) To measure the exact error, center the needle and note the degrees off 0° or 180°; more than 4° and the receiver is out of tolerance. An RMI should indicate 180° regardless of OBS setting (IPH ch. 2; 91.171(b)(1)).

Set the current altimeter setting; the altimeter should indicate within 75 feet of the field elevation. Beyond that, the altimeter's accuracy is questionable and the instrument goes to a repair station — but first recheck in the run-up area, since ramp elevation can differ meaningfully from published field elevation. With no altimeter setting available, set the published field elevation for the preflight check (IFH ch. 5).

• Attitude indicator — erects within about 5 minutes (normally 2–3); horizon bar stays level taxiing straight and tips no more than 5° in taxi turns, or the instrument is unreliable
• Heading indicator — set to the compass after spin-up; before takeoff it should agree with the known runway or taxiway heading within 5°
• Turn coordinator — in taxi turns, miniature aircraft shows the turn direction and the ball swings freely opposite the turn

Listen at power-up too: hesitation or unusual noises as the gyros spin up gets investigated before flight (IFH ch. 5).

• Database current — within its 28-day cycle and supporting the operation; required for IFR GPS (IFH ch. 9)
• Position initialized correctly, and the active flight plan cross-checked against the charts (IPH ch. 2)
• GPS NOTAMs and WAAS status reviewed; RAIM prediction obtained from the receiver or FSS for non-WAAS operations (IFH ch. 9)

Charts count too: en route charts revise every 56 days — an out-of-date chart or database is a Task II.C risk element in itself (IFH ch. 1).

Same ladder as VFR — MEL if one exists; otherwise the item must not be required by the type certificate/equipment list or KOEL, by 91.205, by an AD, or for the operation, then deactivate or remove, placard "Inoperative", record it, and a pilot or mechanic determines it's safe (91.213(d)). The IFR difference: "the operation" now sweeps in 91.205(d) — a dead attitude indicator, clock, or alternator that might placard away for day VFR grounds the airplane for IFR. And a broken transponder or ADS-B can still fly to a repair point, but only with the ATC authorization of 91.215(d)/91.225(g).

• Walk-around — pitot cover off, tube unobstructed; static ports clear and nothing near them disturbing airflow; antennas in good condition
• Records — altimeter/static system tested within 24 calendar months; ELT battery replacement date in the maintenance record
• Paperwork — Chart Supplement and NOTAMs for every NAVAID you'll use; charts and plates for departure, en route, destination, alternate
• Panel — radios off before start; altimeter set and indicating field elevation; magnetic compass full of fluid with a current correction card; clock set and running; alternate static valve opens and closes fully; pitot heat verified by ammeter draw or the POH method (IFH ch. 5)

• Listen to the gyros spin up — no hesitation or odd noises
• Suction gauge (or electrical indicators) — power source appropriate for that aircraft's instruments
• Magnetic compass — card swings freely, bowl full, compare against a known heading while stopped or taxiing straight; note the correction for the runway heading
• Heading indicator — allow about 5 minutes for spin-up, set to the compass; check slaving on a slaved system
• Attitude indicator — erects and holds the correct attitude
• Altimeter — within 75 feet of field elevation
• VSI — reading zero (tap the panel gently if not)
• Radios checked and set; deice/anti-ice checked for operation (IFH ch. 5)

Not necessarily an IFR no-go — the VSI is not a 91.205(d) required instrument. The IFH's ground check expects zero (tap gently first); a stuck non-zero indication is the kind of "possible defect" this task exists to catch, so treat the indicated offset as the instrument's new zero reference in flight, and consider 91.213 handling if it's genuinely failed. Contrast that with the sensitive altimeter, clock, or rate-of-turn indicator — those are GRABCARD items, and a defect there ends the IFR flight (91.205(d); IFH ch. 5).

At and above FL 240, if VOR navigation equipment is required for the route, the aircraft must also have approved DME or a suitable RNAV system. If it fails at or above FL 240, notify ATC immediately — then you may continue to the next airport of intended landing where repairs can be made (91.205(e)).

Not with GPS as your IFR navigation source — an updatable database supporting the operation is required for IFR GPS, and using GPS in place of DME/ADF explicitly requires a current database (IFH ch. 9). Your options are updating it before departure or planning the flight on ground-based navigation appropriate to the route (with the VOR check current, of course). This is IR.II.C.R2 in its purest form: outdated navigation data is an airworthiness problem for the operation, even when the airframe itself is pristine.

Clearance limit, Route (including any DP), Altitude, Frequency, Transponder code — CRAFT. Except for the squawk, I can predict most of it before engine start: the clearance limit is usually the destination, the route is what I filed or the DP in use, and the departure frequency is printed on the charts. I pre-write what I expect, then correct against what the controller actually says (IFH ch. 2).

The fix or airport to which my clearance is valid — normally the destination airport. If I arrive at a clearance limit short of the destination before receiving clearance beyond it, ATC expects me to maintain the last assigned altitude and hold — as charted, or if no pattern is charted, in a standard pattern on the course I approached the fix on — and request further clearance as soon as possible (IFH ch. 10). Holding mechanics are covered under Task III.B.

• Reading the full clearance back to clearance delivery is recommended (IFH ch. 2), and ATC is responsible for ensuring my readback is correct (IPH ch. 1).
• I must read back any part of a clearance containing "hold short" instructions (IPH ch. 1).
• When I'm uncertain of a clearance, I shall immediately request clarification (91.123(a)).
• I request an amended clearance if the one issued would violate a rule, exceed my aircraft's performance or navigation capability, or place me in jeopardy — accepting it makes compliance my problem (IFH ch. 10).

Only when:

• I obtain an amended clearance
• An emergency exists
• The deviation responds to a TCAS resolution advisory

I may also cancel IFR in VFR conditions, except in Class A airspace. After an emergency or RA deviation, I notify ATC as soon as possible (91.123).

As PIC, I can deviate from any rule of Part 91 to the extent required to meet an in-flight emergency (91.3) — including deviating from an assigned clearance immediately when time doesn't permit ATC approval (IFH ch. 2). I notify ATC of the deviation as soon as possible, and if ATC gives me priority, I'm prepared to submit a detailed report within 48 hours to the facility manager, but only if requested (91.123(c), (d)).

At a non-towered airport, my clearance may come with a void time: I must be airborne before that time or the clearance is void — off at exactly the void time is too late (IFH ch. 2). If I don't depart, I must notify ATC by a specified notification time within 30 minutes of the original void time; after the void time my reserved slot in the IFR system is released to other traffic (IPH ch. 1). I can request a specific void time when filing (IFH ch. 2).

The other half of the void-time system. A release time is the earliest I may depart — I do not take off before it (IFH ch. 2). Hold for release means I'm not cleared for takeoff yet because the departure controller can't fit me into the flow; at a towered field, the tower won't issue takeoff clearance until departure issues a release (IFH ch. 2). Having a clearance is not the same as being released.

"Cruise 5,000" assigns a block of airspace from the minimum IFR altitude up to and including 5,000. I may level at any altitude in the block and climb or descend within it at my discretion — but once I report leaving an altitude, I can't return to it without a new clearance. A cruise clearance also authorizes the approach at the destination airport (IFH ch. 10; IPH ch. 2). With an unpublished route, ATC adds a crossing altitude that guarantees obstruction clearance until I join a published segment (IFH ch. 10).

An IFR clearance I request (pilot only, in VFR conditions) to fly a VFR altitude of my choice in lieu of an assigned altitude. I must:

• Fly appropriate VFR altitudes per part 91
• Comply with VFR visibility and cloud-clearance criteria
• Still comply with all IFR rules — minimum IFR altitudes, position reports, course, clearance adherence

I remain on my IFR flight plan, but ATC no longer separates me — see and avoid. Not permitted in Class A (IFH ch. 10). It allows operating above, below, or between layers — not only "on top" (IFH ch. 10).

I squawk 7600, then fly what ATC can predict (91.185; IPH ch. 2):

• Route — in order of precedence: Assigned, Vectored, Expected, Filed
• Altitude — the highest of the minimum IFR altitude, the expected altitude, or the assigned altitude, re-evaluated for each route segment
• If the failure occurs in VFR conditions, or I encounter them after it: I remain VFR and land as soon as practicable (91.185(b))

The full procedure — mnemonics, clearance-limit timing, and worked examples — is covered under Task VII.A.

The last clearance received supersedes all previous clearances — the 2,000-foot restriction is canceled. This applies in both terminal and Center airspace (IFH ch. 2).

Advise ATC immediately if unable to comply — before accepting, ideally. I'm expected to request an amended clearance any time one is unacceptable from a safety perspective, exceeds my navigation capability, or would cause me to break a regulation. For DPs specifically, I must be able to meet the published climb gradient; if I can't, I must wait for VMC to depart (IPH ch. 1). If a speed adjustment is issued, I'm expected to hold it ±10 knots or say I can't (IFH ch. 10).

I may not operate on a clearance or instruction issued to another aircraft for radar air traffic control purposes (91.123(e)). The defense is strict radio discipline: I use my complete call sign on every transmission, and I'm suspicious when a clearance doesn't match what I expected — query rather than assume (IPH ch. 4). A readback with my full call sign gives the controller the chance to catch the mix-up; readback/hearback errors are a documented cause of altitude and course deviations (IPH ch. 2).

Over each compulsory reporting point — the solid triangles on the en route chart — regardless of altitude, including VFR-on-top. On direct routes, over each fix used to define the route. Open-triangle points are reported only on ATC request. Discontinue reporting when ATC says "radar contact"; resume when I hear "radar contact lost" or "radar service terminated" (IFH ch. 10).

1. Identification
2. Position
3. Time
4. Altitude or flight level (actual altitude when VFR-on-top)
5. Type of flight plan (not needed when reporting directly to ARTCC or approach)
6. ETA and name of the next reporting point
7. Name only of the succeeding reporting point
8. Pertinent remarks (IFH ch. 10)

At all times:

• Vacating any assigned altitude for a new one
• Any altitude change when VFR-on-top
• Unable to climb or descend at least 500 fpm
• A missed approach (with my request)
• Average TAS change of 5 percent or 10 knots (whichever is greater) from the flight plan
• Time and altitude reaching a holding fix, and when leaving it
• Loss of nav or comm capability (VOR, ADF, GPS anomaly, ILS, air/ground comm)
• Anything affecting safety of flight

When not in radar contact, add: leaving the final approach fix (FAF) or outer marker inbound, and a corrected ETA when my estimate is off by more than 3 minutes (IFH ch. 10).

Standard: right turns. Nonstandard: left turns. When ATC issues holding instructions for an uncharted hold, the clearance states the turn direction if left turns are to be made (AIM 5-3-8; IFH ch. 10); a charted nonstandard pattern carries its turn direction on the chart, so "HOLD EAST AS PUBLISHED" may never say "left turns."

No-wind anatomy of a standard pattern:

1. Fly the inbound course to the fix.
2. Turn 180° right.
3. Fly a parallel outbound leg for 1 minute.
4. Turn 180° right.
5. Fly the inbound course back to the fix (IFH ch. 10).

Charted patterns take precedence — hold as depicted unless ATC says otherwise (AIM 5-3-8).

• Direction of holding from the fix — one of the eight cardinal points (N, NE, E…)
• Holding fix (may be omitted if it's already the stated clearance limit)
• Radial, course, bearing, airway, or route to hold on
• Leg length in miles if DME or RNAV is used (in minutes on pilot request or if the controller considers it necessary)
• Direction of turn if left turns apply
• Expect-further-clearance (EFC) time and any additional delay information (AIM 5-3-8; IFH ch. 10)

If the pattern is charted, ATC may shorten this to "HOLD EAST AS PUBLISHED" — and must give complete instructions if you ask (AIM 5-3-8).

Ask ATC before reaching the fix. If you can't get instructions (frequency congestion, stuck mic), enter a standard pattern on the course you approached the fix on, at your last assigned altitude, and request further clearance as soon as possible — your altitude at the clearance limit is protected (AIM 5-3-8; IFH ch. 10).

Exceptions: patterns from 6,001–14,000 ft may be restricted to 210 KIAS (icon); any pattern may carry a charted restriction such as (175); USAF fields 310, Navy fields 230; climb-in-holding allows 310 KIAS unless a lower maximum is published. Unable to comply? Notify ATC (AIM 5-3-8).

Start the reduction when 3 minutes or less from the holding fix, so you cross the fix initially at or below the maximum holding airspeed — the protected airspace is sized for compliant entries, and excess speed at the fix can carry you outside it, especially where adjacent patterns are close together (IFH ch. 10; AIM 5-3-8). The ACS adds the practical point: set power as needed for fuel conservation once slowed (IR.III.B.S2).

Sector boundaries come from a line at 70° to the holding course on the holding side (AIM 5-3-8):

• Parallel — sector (a): fly to the fix, turn to parallel the holding course outbound on the nonholding side for 1 minute, then turn through more than 180° in the direction of the pattern and return to the fix or intercept the inbound course.
• Teardrop — sector (b): fly to the fix, turn outbound to a heading for a 30° teardrop on the holding side for 1 minute, then turn in the direction of the pattern to intercept the inbound course.
• Direct — sector (c): fly to the fix and turn to follow the pattern.

Determine the entry from your heading arriving at the fix; ±5° is within good operating limits (AIM 5-3-8).

Inbound leg target: 1 minute at or below 14,000 ft MSL, 1.5 minutes above (AIM 5-3-8). Fly the initial outbound leg 1 (or 1.5) minutes, then adjust subsequent outbound legs to make the inbound leg come out right. Outbound timing begins over or abeam the fix, whichever occurs later; if you can't determine the abeam position, start when the turn to outbound is complete (AIM 5-3-8; IFH ch. 10).

Compensate for known wind on the legs, not in the turns (IFH ch. 10). Outbound, triple the inbound drift correction to avoid major turning adjustments — correcting 8° left inbound means 24° right outbound (AIM 5-3-8). Then adjust outbound time so the inbound leg still comes out to 1 (or 1.5) minutes.

Same entries and procedures, but legs are distances instead of times. The controller or the chart specifies the outbound leg length; the end of the outbound leg is determined by the DME or along-track-distance readout. Watch the geometry: inbound toward the NAVAID with the fix at 10 DME and 5-mile legs, the outbound leg ends at 15 DME; inbound away from the NAVAID with the fix at 28 DME and 8-mile legs, it ends at 20 DME (AIM 5-3-8).

• The time and altitude at which you reach the holding fix or clearance limit
• When you leave the holding fix (AIM 5-3-8; IFH ch. 10)

ATC needs your departure time from the fix before the vacated airspace can be given to anyone else (IFH ch. 10).

The expect-further-clearance time in your holding instructions — ATC's estimate of when you'll be cleared beyond the fix, along with any pertinent additional delay information (AIM 5-3-8; IFH ch. 10). It matters twice: it's your lost-comm exit time from the clearance limit (91.185(c)(3)), and it's the number you plug into a fuel recalculation the moment it's assigned (IR.III.B.R1).

Whichever requires the least bank (AIM 5-3-8):

• 3° per second, or
• 30° bank angle, or
• 25° bank when a flight director is used

One more cue for the classic case: holding at a VOR, start the turn outbound at the first complete reversal of the TO/FROM indicator (AIM 5-3-8).

Recalculate fuel (IR.III.B.R1). You planned under 91.167 with fuel to the destination, then the alternate (if required), then 45 minutes at normal cruise — an unanticipated hold spends that margin. Compare fuel remaining at the EFC against what the approach, the missed, and the trip to the alternate will need, and decide now what EFC you can't accept (91.167) — the endurance arithmetic is worked under Task I.C.

Advising "minimum fuel" tells ATC that upon reaching the destination you can't accept any undue delay. It is not an emergency and confers no priority — it's a heads-up that an emergency is possible if delay occurs. State it on initial contact after your call sign. If you actually need priority to land safely, declare an emergency due to low fuel and report fuel remaining in minutes (AIM 5-5-15).

1. When ATC issues further clearance en route or approach clearance
2. As prescribed by part 91 — the lost-comm rules of 91.185 or PIC emergency authority under 91.3
3. After canceling IFR, if you're holding in VFR conditions (IFH ch. 10)

If ATC instead specifies a time to depart the fix, adjust your pattern within the hold to cross the fix at that exact time (AIM 5-3-8) — that's the ACS skill of arriving over the fix as close as possible to a specified time (IR.III.B.S5).

Yes — established in a published pattern above the published minimum holding altitude, approach clearance lets you descend to that published minimum holding altitude. Where no minimum holding altitude is published, maintain the last assigned altitude until you leave the hold established on the inbound course; then the route segment's published minimum applies (AIM 5-3-8).

Deteriorating destination weather is the classic scenario — everyone arrives, everyone needs the approach, and the stack forms (IR.III.B.R3). ATC also holds you when weather is reported below your minimums while you wait for improvement, and issues instructions when a delay will exceed 1 hour or a revised EFC is needed (IFH ch. 10). If the destination trend is down, expect the hold, know your holding fuel burn, and have the alternate decision pre-made.

That the retrieved pattern matches the assigned or charted hold in turn direction, speed limit, timing, and distance — multiple different holds can exist at the same fix, and many systems store only one, or store everything as standard right turns. For an ATC-assigned uncharted hold, you're responsible for programming course, turn direction, and leg length or time yourself. Changes made near the fix may not take effect until the next circuit (AIM 5-3-8).

• Reduced bank angles — if the bank limit is pilot-selectable, use at least 25°, or advise ATC you need more room
• Fly-by turns at the fix on entry instead of flying over it
• Turning outbound beyond the design turn point when a leg distance is coded as an inbound-leg maximum — worst with a strong headwind outbound
• Wrong speed/timing parameters — a hold loaded above 14,000 ft can retain 1.5-minute legs after you descend below it

Slowing to holding speed at least 3 minutes out and monitoring the outbound leg length are the defenses (AIM 5-3-8).

• Altitude ±100 feet during level flight
• Selected headings ±10°
• Airspeed ±10 knots
• Bank angles ±5° during turns

The examiner is also grading the process — proper cross-check, interpretation, and pitch/bank/power/trim corrections (IR.IV.A.S2).

Control and performance — set an attitude on the attitude indicator and a power setting, then confirm the result on the performance instruments.

Primary and supporting — for each maneuver, classify instruments by control function: one instrument is primary for pitch, one for bank, one for power, and the rest support it.

Both use the same instruments and the same control responses — they differ in how much they lean on the attitude indicator versus interpreting the others (IFH ch. 6).

Three groups:

• Control — immediate attitude and power indications: attitude indicator plus power indicators (manifold pressure, tachometer, fuel flow)
• Performance — what the airplane is actually doing: altimeter, ASI, VSI
• Navigation — position relative to a facility or fix

Four steps: establish an attitude and power setting on the control instruments, trim until control pressures are neutralized, cross-check the performance instruments for the desired result, and adjust attitude and/or power as necessary (IFH ch. 6).

The primary instrument gives the most pertinent information for the maneuver — usually the one that should hold a constant indication. In straight-and-level flight:

• Altimeter — primary for pitch
• Heading indicator — primary for bank
• Airspeed indicator — primary for power

The attitude indicator and the rest support them (IFH ch. 6).

Eyes stay on the attitude indicator 80–90 percent of the time, with quick glances out to one performance instrument and back — AI, altimeter, AI, heading indicator, AI, airspeed, and so on. The eyes never travel directly between the flight instruments; the AI anchors the scan because it is the one instrument showing pitch and bank in a single glance. The maneuver determines which instruments join the pattern (IFH ch. 6).

• Fixation — staring at a single instrument, e.g., wondering how the altimeter got 200 feet low while heading wanders off
• Omission — dropping an instrument, e.g., leveling off a steep turn on the AI alone and missing the heading drift caused by its precession error
• Emphasis — relying on the instrument that is easiest to read instead of the combination; the AI alone can't hold altitude with precision (IFH ch. 6)

3° per second — a complete 360° circle in 2 minutes. The bank required increases with speed: rule of thumb is 15 percent of true airspeed, computed by dividing airspeed by 10 and adding half the result — at 100 knots about 15° (100 ÷ 10 = 10 + 5), at 120 knots about 18°. Roll in on the attitude indicator, then hold the turn coordinator's standard-rate indication as primary bank (IFH ch. 7).

Start the level-off at about 10 percent of the vertical speed — climbing at 500 fpm, lead by 50 feet; at 1,000 fpm, lead by 100 feet. Same rule applies to leading the roll-out of a turn: lead the desired heading by half the bank angle (IFH ch. 7).

A warning flag or an inconsistency between the attitude indicator and the supporting performance instruments. Maintain aircraft control first, expedite the cross-check to include every instrument, and compare the AI against the turn indicator and VSI — that comparison checks the vacuum/pressure, electrical, and static systems against each other so you can isolate the failed component and fly on what remains (IFH ch. 11).

Once the airplane stabilizes at climb speed and attitude:

• Airspeed indicator — primary for pitch (airspeed is what you're holding; small pitch changes correct it)
• Heading indicator — primary for bank, as in straight-and-level
• Tachometer or manifold pressure — primary for power, confirming the climb power setting

During the entry itself, before things stabilize, the attitude indicator is your pitch reference while the ASI catches up (IFH ch. 7).

As power comes up, the ASI is primary for pitch until the vertical speed approaches the target. Once the VSI needle stabilizes, the roles swap: VSI primary for pitch, ASI primary for power — you hold the rate with pitch and the airspeed with power. Prompt, closely coordinated pitch-and-power corrections are the whole game: vertical speed correct but airspeed low — add power; vertical speed high and airspeed low — lower the nose slightly first (IFH ch. 7).

Entry — effective with or without an attitude indicator: reduce airspeed to the selected descent speed in level flight, then make a further power reduction to a predetermined setting, simultaneously lowering the nose to hold airspeed constant, and trim off the pressures.

Constant-airspeed descent: any deviation from the desired airspeed calls for a pitch adjustment (ASI primary for pitch).

Constant-rate descent: same entry, but the VSI becomes primary for pitch once it stabilizes near the target rate, and the ASI primary for power — closely coordinated pitch-and-power corrections, just as in climbs.

Leveling off at an airspeed higher than descent speed takes more lead — at 500 fpm, about 100–150 feet; leveling off at descent airspeed, about 50 feet, adding power as the pitch comes up (IFH ch. 7).

• Turn coordinator — primary for bank (the AI supports it; note the AI's bank angle when the TC shows standard rate)
• Altimeter — primary for pitch
• ASI — primary for power; as bank steepens, vertical lift decreases and drag rises, so expect a pitch and power touch-up

Rolling out, the AI becomes primary bank until roughly level, then the heading indicator takes over. In a timed turn, the clock replaces the heading indicator — at standard rate the airplane turns 45° in 15 seconds (IFH ch. 7).

The common procedure is to underpower or overpower the target power setting — overshoot it to accelerate the airspeed change, then set the known cruise value — while the altimeter stays primary for pitch and the heading indicator stays primary for bank throughout. During the change the manifold pressure gauge (or tachometer) becomes primary for power; once airspeed settles, the ASI takes the role back. Expect trim and control-pressure changes around all axes as power changes — a single-engine airplane yaws and rolls left as power comes in — so cross-check speed has to rise (IFH ch. 7).

• Older (spillable) units tolerated only about 60° of pitch and 100° of roll — beyond that the gyro tumbled, hence the caging mechanism; newer instruments do not have these tumble limits
• Gyro erection takes 2–3 minutes after start (up to 5)
• Slight nose-up indication during rapid acceleration, nose-down during rapid deceleration
• Small pitch-and-bank error after a 180° turn — these inherent errors self-correct within about a minute of straight-and-level flight (IFH ch. 5)

VSI: the pointer lags a few seconds behind the actual pressure change, but it is more sensitive than the altimeter and excellent as a trend instrument; an IVSI (instantaneous VSI) uses accelerometer-driven pumps to remove most of the lag. If the VSI shows a small climb or descent in known level flight, it's out of calibration — use that indication as your zero.

ASI: lags on pitch changes, not from instrument construction but from the airplane's momentum: a rapid airspeed change means a large pitch change happened a moment ago (IFH ch. 5, ch. 7).

A non-slaved gyro heading indicator isn't north-seeking — you set it from the magnetic compass. The Earth rotates 15° per hour while the gyro holds its position in space, producing apparent drift, on top of mechanical precession. Standard practice: compare it with the magnetic compass at least every 15 minutes (in straight, level, unaccelerated flight) and reset as necessary (IFH ch. 5).

The semicircular canals sense angular acceleration through fluid deflecting sensory hairs. In a prolonged constant-rate turn the fluid catches up with the canal walls, the hairs straighten, and the brain concludes the turn has stopped. Rolling out then swings the fluid the opposite way — a false sensation of turning in the opposite direction — and the disoriented pilot may roll right back into the original turn. The otolith organs add their own lie: forward acceleration feels like tilting the head back, i.e., a false climb (IFH ch. 3).

Illness, medication, alcohol, fatigue, sleep loss, and mild hypoxia all increase susceptibility to spatial disorientation — being physically tuned for flight is a listed countermeasure, not a nicety. In flight:

• Avoid sudden head movements, especially during takeoff, turns, and approach
• If you drop something, retrieve it with minimal head movement (coriolis)
• Use only reliable fixed points when outside references are available
• Above all, become proficient on the instruments and trust them over your sensory perceptions — the sensations can't be prevented, only overridden (IFH ch. 3)

Flying an electronic-flight-display airplane without using the autopilot has been shown to increase workload and decrease situational awareness for pilots still learning the system — the scan you've automatized on round dials doesn't transfer for free to tapes and trend vectors. The flip side is also tested: the autopilot should be used to reduce workload, which buys attention for monitoring the flight. Know the display, the failure annunciations, and the automation modes before you take an unfamiliar panel into IMC (IFH ch. 6, ch. 7).

An attitude not normally required for instrument flight.

Causes:

• Turbulence
• Disorientation
• Instrument failure
• Confusion
• Preoccupation with flight deck duties
• Carelessness in cross-checking
• Errors in instrument interpretation
• Lack of proficiency in aircraft control

Because they're unintentional, they arrive unexpected — and the untrained reaction is instinctive and abrupt rather than deliberate (IFH ch. 7).

Any time you note an instrument rate of movement or indication not associated with the basic maneuvers, assume an unusual attitude and increase the speed of your cross-check to confirm it — attitude, instrument error, or instrument malfunction. Once confirmed, the immediate problem is not how the airplane got there — it's what it's doing and how to get back to straight-and-level (IFH ch. 7).

Panel: altimeter and VSI showing a climb, airspeed decreasing, plus the AI indication (unless the attitude is extreme).

Recovery — almost simultaneously, but in this sequence:

1. Add power in proportion to the observed deceleration
2. Forward elevator to lower the nose and prevent a stall
3. Level the wings with coordinated aileron and rudder, centering the ball (IFH ch. 7)

Panel: altimeter and VSI showing a descent, airspeed increasing.

Recovery — by the numbers:

1. Reduce power to prevent excessive airspeed and altitude loss
2. Level the wings with coordinated aileron and rudder, referencing the turn coordinator
3. Raise the nose to level flight attitude with smooth back elevator pressure (IFH ch. 7)

Pulling while banked tightens the turn instead of raising the nose — that's the graveyard-spiral mechanism: back pressure in a spiral steepens the descent and increases the load. And the instinctive reaction to a nose-down attitude is precisely to pull back on the elevator, so the sequence has to be trained until it overrides the instinct. Keep the ball centered too — slipping and skidding sensations aggravate disorientation and retard recovery (IFH ch. 3, ch. 7).

Not blindly. A spillable AI may have exceeded its upset limits or failed — it might be what put you here. Even a properly operating nonspillable unit can show errors up to 5° of pitch and bank, and its indications are hard to interpret in extreme attitudes. Follow the POH/AFM recovery procedure if one is published; otherwise recover by reference to the ASI, altimeter, VSI, and turn coordinator (IFH ch. 7).

Level pitch is indicated by the reversal and stabilization of the ASI and altimeter needles; straight coordinated flight by the level miniature aircraft of the turn coordinator and a centered ball. After the initial inputs, keep a fast cross-check going for overcontrolling — the first corrections may be large. As ASI, altimeter, and turn coordinator stabilize, bring the AI back into the scan, then return to your assigned altitude (IFH ch. 7).

• Failure to keep the airplane trimmed — an interruption while holding pressures is a classic entry
• A disorganized flight deck — hunting for charts steals the scan
• Slow cross-check and fixation on the offending instrument
• Attempting to recover by sensory sensations instead of sight
• Failure to practice basic instrument skills — every basic-skill error is amplified in a recovery (IFH ch. 7)

Rapid acceleration stimulates the otoliths exactly like tilting the head backwards — the somatogravic illusion of a nose-up attitude. A disoriented pilot pushes over into a dive, especially without good visual references, as on a night IMC takeoff. Rapid deceleration reverses it: a false nose-down sensation invites a pull into a nose-up or stall attitude. An abrupt push from climb to level flight can even feel like tumbling backwards (inversion illusion), provoking a further push. Recovery by feel doesn't just fail — it actively deepens the attitude, which is why "recover by sensory sensations other than sight" is a listed common error (IFH ch. 3, ch. 7).

Precursors — all act by interrupting the cross-check:

• Stress
• Task saturation
• Inadequate instrument scan
• Distractions
• Spatial disorientation

The IFH's matching errors: improper trimming (a distraction while holding pressures becomes an emergency when the scan stops) and poor single-pilot resource management (a disorganized flight deck causing you to stop cross-checking long enough to enter an unusual attitude).

What breaks the chain:

• Trim to hands-off after every change
• Arrange the flight deck before entering IMC
• Keep the scan moving no matter what else is happening (IFH ch. 7)

Each recovery is flown against an edge of the envelope:

• Nose-high — airspeed is decaying toward a stall, which is why power and forward elevator come first
• Nose-low — airspeed is building, so reduce power to prevent excessive airspeed and altitude loss before raising the nose
• Load factor — pulling while banked raises the load factor, and stall speed increases with the square root of the load factor — so a hard pull can produce an accelerated stall or, past the limit load factor, structural damage. That's the aerodynamic case for wings level before back pressure: the graveyard-spiral pull only tightens the turn, steepens the descent, and increases the load (IFH ch. 3, ch. 4, ch. 7)

The primary flight display (PFD) keeps the attitude display in view at all times and adds recovery cues:

• Red chevrons point back to the horizon line in nose-high and nose-low attitudes; they appear as the aircraft approaches 30° nose-up and when pitch exceeds 15° nose-down
• The screen de-clutters in extreme attitudes — approaching 30° nose-up (information reappears below 25°), at 20° nose-down (reappears above 15°), and at 65° of bank (reappears below 60°) — leaving only what recovery needs; past 60° of bank the roll index extends to show the shortest way back to wings level
• The horizon line never fully leaves the display: a sliver of brown stays visible in extreme nose-up, blue in extreme nose-down, always showing the quickest way back

Caution: the white line is the horizon; the blue/brown break is only a reference. And an attitude and heading reference system (AHRS) failure removes all of this protection along with the attitude and heading displays (IFH ch. 7).

Two roles:

• Prevention — the autopilot should be used to reduce workload, which gives you more time to monitor the flight and decreases the chance of entering an unusual attitude in the first place
• Degraded-panel aid — the autopilot's roll mode is driven by its own turn coordinator mounted behind the multi-function display (MFD), independent of the AHRS; with an AHRS and ADC failure the manufacturer recommends turning the autopilot on as a wing leveler while you fly the standby instruments

Know your specific system's failure behavior: losing the AHRS costs all autopilot modes except roll and altitude hold (IFH ch. 7).

• Fly the aircraft first — the IFH's rule for any emergency encounter: the first order of business is aircraft control, and the workload spike demands increased concentration on the instrument scan
• Trust the instruments over every bodily sensation — the transition moment is peak disorientation risk
• Use the automation if equipped — engaging the autopilot cuts workload and buys monitoring capacity
• Get help early — advise ATC of the situation and, if necessary, declare an emergency before the situation deteriorates beyond your ability to recover; as an instrument-rated pilot, an in-flight clearance is usually one transmission away

PIC emergency authority is covered under Task III.A, and lost-comm procedures under Task VII.A (IFH ch. 3, ch. 11).

Once the airplane is under control on instruments:

• Climb — wings level on the AI, hold heading (turn only to avoid known obstacles), adjust power for the climb. An immediate climb increases separation from terrain and obstacles and improves ATC radar reception
• Divert toward better conditions — abandon continued flight into deteriorating weather and maneuver back toward conditions that support visual flight
• Transition to IFR — get a clearance, then request a vector to VFR conditions or to the nearest suitable airport and fly an instrument approach (ILS or GPS if equipped) down through the layer
• If IMC is re-entered while circling or in a visual segment of an approach, the best remedy is immediate execution of the published missed approach (IPH ch. 7, app. A)

• Terrain and obstacles — a nose-low attitude is converting altitude into airspeed, and the recovery itself costs more altitude; know the minimum safe altitude where you are, and remember that climbing increases separation from terrain and man-made obstacles
• Traffic — under IFR, the excursion has likely taken you off your assigned altitude, the basis of your separation: after stabilizing in straight-and-level flight, return to the assigned altitude and advise ATC. In VMC, see-and-avoid still applies — a traffic display (TIS) is an aid, not a replacement, and shows only targets within its limited service volume (IFH ch. 7, ch. 11; IPH app. A)

Everything in the causal list is a IV.A discipline failing:

• Flight causal — untrimmed airplane, slow or fixated cross-check, interpretation errors
• Physiological — illness, medication, alcohol, fatigue, sleep loss, mild hypoxia raising disorientation susceptibility; sudden head movements triggering coriolis
• Environmental — turbulence, lack of outside references
• System and equipment failures — a failed AI or vacuum pump quietly feeding you a false attitude, which is why failure recognition is a cross-check skill: an inconsistency between the AI and the supporting instruments, confirmed by comparing systems against each other

The recovery task exists for when prevention fails — but the examiner wants to hear prevention first (IFH ch. 3, ch. 5, ch. 7, ch. 11).

The VOR must be maintained under an approved procedure, or operationally checked within the preceding 30 days and found within limits — ±4° for ground-based checks and the dual-VOR cross-check, ±6° airborne — and whoever checks it logs date, place, bearing error, and signature (91.171). The check methods, their preference order, and the VOT procedure are covered under Task II.C.

1. Orient — determine the radial you're on (center the CDI with FROM)
2. Parallel the desired course to keep left/right straight
3. Take the difference between your radial and the one to intercept, then double it for the intercept angle — not less than 20°, not more than 90°
4. Set the OBS to the desired course, turn to the intercept heading
5. Hold that heading until the CDI centers, leading the turn as you gain experience (IFH ch. 9)

Bracketing. Follow the needle with an initial 20° correction; when it re-centers, take half the correction out. Each time the needle drifts, re-correct and halve again until you find the wind correction angle that holds the course. Chasing the needle without a reference heading turns tracking into homing (IFH ch. 9).

With the OBS set to the reciprocal of your intended course, the CDI deflects away from the course — correcting toward the needle takes you farther off. The fix is procedural: always set the OBS to agree with your intended course, inbound or outbound (IFH ch. 9).

The azimuth card is slaved to heading, so the needle always shows bearing directly: the head of the needle shows magnetic bearing TO the station, and the tail of the needle shows the radial you're on (bearing FROM). For a fixed-card ADF, add relative bearing to heading: MH + RB = MB to the station (IFH ch. 9).

DME (UHF, paired with the VHF facility frequency) times interrogation pulses and displays slant range — the straight-line distance from your antenna, not ground distance. Directly over the station it reads your altitude in NM. The error is negligible when you're at least 1 NM from the station for every 1,000 feet above it. Displayed groundspeed is accurate only tracking directly to or from the station (IFH ch. 9).

• Track to the station on the lead radial; at 150 knots groundspeed or less, lead the turn by 0.5 NM
• Turn approximately 90° and roll out with the bearing pointer on the wingtip
• Let the pointer drift 5°–10° behind the wingtip, then turn toward the station to put it 5°–10° ahead — a series of short, straight legs
• Correct 10°–20° toward the facility for each half-mile outside the arc; staying slightly inside keeps the arc turning toward you

The ACS tolerance is ±1 NM (IFH ch. 9; IR.V.A.S6).

Receiver Autonomous Integrity Monitoring — the receiver's self-check that the satellite geometry supports the integrity required for the phase of flight. It needs 5 satellites, or 4 plus baro-aiding, to detect an anomaly; fault detection and exclusion (FDE) needs 6 satellites (or 5 with baro-aiding) to also isolate and remove the bad one. Without RAIM you have no assurance the GPS position is trustworthy (AIM 1-1-17, IFH ch. 9).

Use the receiver's own prediction function, a manufacturer tool, the FAA Service Availability Prediction Tool (SAPT), or ask FSS — briefers give RAIM status for 1 hour before to 1 hour after your ETA unless you ask for a window, and you should also request one for the departure airport when flying a GPS departure. If RAIM is predicted unavailable: rely on other approved navigation, re-route, delay, or cancel (AIM 1-1-17, IFH ch. 9).

For a basic (non-WAAS) IFR GPS:

• En route: ±5 NM full scale
• 30 NM from the airport the receiver annunciates arm — armed, it scales to ±1 NM terminal sensitivity
• 2 NM before the final approach waypoint (FAWP) the approach mode goes active and sensitivity ramps smoothly to ±0.3 NM at the FAWP

If the approach mode never arms, sensitivity never ramps down — the equipment flags, and you fly to the missed approach waypoint (MAWP) and go missed. WAAS receivers switch to ILS-like angular scaling on LNAV/VNAV and LPV finals (AIM 1-1-17, 1-1-18; IFH ch. 9). What WAAS itself adds — accuracy, integrity, availability, and the TSO approvals behind it — is covered under Task II.B.

• Airspeed: ±10 knots
• Altitude: ±100 feet
• Headings: ±5° — tighter than the ±10° used elsewhere
• Course: within ¾-scale CDI deflection
• DME arc: ±1 NM

These are the tolerances for this task (IR.V.A.S5–S6). If navigation, approach, or communication equipment fails under IFR in controlled airspace, report it to ATC — aircraft ID, equipment affected, degree of impairment, and assistance desired (91.187; IR.V.A.S7).

Rotate the OBS until the CDI centers with a FROM indication — the course index shows the radial you're on; the inbound course is its reciprocal. One station only puts you somewhere on a line: cross-cut a second NAVAID (or use DME) to pin down a fix. Near the station, expect the needle to fluctuate in the zone of confusion — rapid or fluctuating movement means station passage is imminent, and positive passage is the TO/FROM flip (IFH ch. 9).

Ground-station course alignment is generally within ±1°. Receiver sensitivity check: with the CDI centered, rotate the OBS until the needle rests on the last dot — that should take 10°–12° or less. Two quirks worth knowing: certain prop RPM settings can modulate the signal and swing the CDI up to ±6° (change RPM before writing up the radio), and terrain can cause brief course roughness (IFH ch. 9).

Sensitivity. The localizer course is only about 5° wide, so full-scale deflection is roughly 2.5° either side of centerline — several times touchier than a 10–12° full-scale VOR. Use shallower intercept angles and half-standard-rate turns near the course, and start corrections the moment the needle moves (IFH ch. 9). Full localizer anatomy — frequencies, course width, service volume — is covered under Task VI.B.

No RMI: use the OBS-and-CDI method — after the 90° intercept turn, center the CDI; your heading sits near the left/right (90°/270°) reference of the card. Hold heading, and each time the CDI drifts 2°–4° from center, re-center it and note the new reference heading, using DME to fine-tune in or out.

Leaving the arc: at 150 knots or less the lead radial is under 5° — no different from intercepting a radial from a straight course. When a charted lead radial gives 7° of lead onto a localizer, use a half-standard-rate turn until the needle starts moving toward center (IFH ch. 9).

An IFR-certified GPS may substitute for ADF/DME to:

• Identify a DME fix
• Fly a DME arc
• Navigate to/from or hold over an NDB/compass locator
• Identify fixes made of an NDB bearing or DME distance

Conditions: the fix or facility must come from the current database (no manual lat/long), integrity monitoring must be working, and the CDI set to terminal (±1 NM) sensitivity in the terminal area. GPS cannot substitute for the lateral guidance source on the final approach of a DME- or ADF-based approach (IFH ch. 9).

An updatable IFR database is required. For en route and terminal operations you may fly with an expired database if you verify the data are correct (waypoints unchanged); for approaches the database must be current, or you must verify the procedure hasn't been amended since it expired. Approaches must be retrievable from the database by name — building one from user waypoints is prohibited, and flying point-to-point doesn't give you approach RAIM or 0.3 NM scaling (AIM 1-1-17; IFH ch. 9).

Two flavors: "not enough satellites" — RAIM can't monitor at all, so the position may be fine but its integrity is unknown; and "integrity alert" — RAIM detected an error exceeding the limit for the phase of flight. Either one on an approach means don't descend: fly to the MAWP and execute the missed. En route, revert to your alternate means of navigation and start actively monitoring it — that's the one time monitoring the backup NAVAID becomes mandatory rather than good practice (AIM 1-1-17; IFH ch. 9).

• Onboard electronics — certain receivers, transceivers, mobile radios, and portable receivers can cause signal interference, and some VHF transmissions cause "harmonic interference". Isolate it by relocating portables, changing frequencies, or turning off suspects while watching the receiver's signal quality page
• Antenna shadowing — the airframe can block the GPS antenna, notably while banked; terrain does the same in valleys surrounded by high ground
• Constellation status — with fewer than 24 operational satellites, GPS may be unavailable at certain locations; satellite status is published through the NOTAM system

Any of these can cost you signal or integrity with no ground station to call about it (IFH ch. 9).

Know what the box is flying before it flies it. Verify the active waypoint and leg — the same waypoint can appear more than once in a procedure (IAWP, FAWP, MAWP on a procedure turn), and skipping fly-over waypoints can leave the receiver sequenced to the wrong leg; some segments demand manual sequencing or a manually set course (IFH ch. 9). Also confirm the autopilot's annunciated roll and pitch modes after every selection — armed is not captured, and the AFM's procedures and limitations govern its use (IPH ch. 4).

The evaluator may have you fly course intercepts with the autopilot (IR.V.A.S9).

These factors erode situational awareness (IFH ch. 11):

• Distractions
• Unusual or unexpected events
• Complacency
• High workload
• Unfamiliar situations
• Inoperative equipment

In this task the classic trap is fixation — staring at one needle until heading and altitude wander, or chasing the CDI instead of flying reference headings. The warning sign is a reactive mindset: the airplane keeps doing things you didn't anticipate. Recovery: fly the airplane first, then reassess and rebuild the picture from additional sources — navigation instruments, the multi-function display (MFD)/moving map, or ATC (IFH ch. 7, ch. 11).

• ODP — Obstacle Departure Procedure: exists purely for obstruction clearance, no ATC flow requirements. Textual, printed in the TPP Takeoff Minimums section; charted graphically only when complex, with "(OBSTACLE)" in the title.
• SID — Standard Instrument Departure: an ATC-requested route for traffic flow, workload, and noise abatement — obstacle protection is considered, but flow is the point. Always charted graphically (IPH ch. 1).

That you cross the departure end of the runway (DER) at least 35 feet up, climb to 400 feet above DER elevation before the first turn, and climb at least 200 ft/NM until reaching the minimum IFR altitude — unless a higher gradient is published. TERPS assumes all engines operating; engine-out contingency planning is entirely on you, the operator (IPH ch. 1).

Departures are assessed against a 40:1 obstacle clearance surface; wherever something penetrates it, an ODP must be developed — one per runway, only at airports with instrument approaches. It's the default IFR departure, flyable without an ATC clearance in the absence of radar vectors or a SID, and at a nontowered field in IMC you'd be foolish to skip it.

If nothing penetrates the surface, the runway passes the diverse departure assessment instead: no ODP is published, and you may climb in any direction, protected until obstacle clearance grows to 1,000 feet (non-mountainous, about 25 NM out) or 2,000 feet (mountainous, about 46 NM); beyond that, off a published route and below the MEA/MOCA or an assigned altitude, terrain is your problem (IPH ch. 1).

• You can meet the required performance — if you can't make the climb gradient, you must not accept the procedure
• You can navigate to the accuracy required
• You possess the charted procedure
• You understand the SID in its entirety

Don't want SIDs at all? File "NO SIDs" in remarks — ATC then clears you via your filed route where possible (IPH ch. 1).

An abbreviated clearance: comply with the SID's lateral path and all published speed and altitude restrictions. "Climb via the WILIT departure except cross 30 north of CHUCK at or above FL 210" keeps the whole procedure but swaps one restriction. Expanded climb-via procedures live in the AIM — know where they are before an examiner hands you one (IPH ch. 1).

Convert to feet per minute using groundspeed: fpm = gradient × GS ÷ 60. At 90 knots groundspeed that's 350 × 90 ÷ 60 = 525 fpm — climbing, in IMC, possibly heavy on a warm day at altitude. The front matter of every TPP has a rate-of-climb table doing this math for you. Compare against your POH climb performance at weight and density altitude before accepting, and tell ATC if unable (IPH ch. 1).

Obstacles within 1 NM of the DER that penetrate the 40:1 surface but are too close for a meaningful published gradient — think trees and poles just off the pavement. They're listed in the TPP Takeoff Minimums and (Obstacle) DP section by distance and bearing, and you avoid them by seeing and avoiding, delaying the turn, or improving the initial climb — a published 200 ft/NM won't save you from a 40-foot tree 300 feet past the runway (IPH ch. 1).

• Victor airways — VOR-based, 1,200 feet AGL up to but not including 18,000 MSL, 4 NM each side of centerline; typically odd numbers north/south, even east/west
• Jet routes — Class A, 18,000 to FL 450, "J" prefix
• T-routes — RNAV (GPS or GPS/WAAS required), low-altitude structure, charted in blue
• Q-routes — RNAV, high-altitude structure (IFH ch. 1; AIM 1-1-17)

MEA — Minimum En Route Altitude: lowest published altitude guaranteeing both obstacle clearance (1,000 ft non-mountainous / 2,000 ft mountainous) and navigation signal reception for the segment. Communication is not guaranteed.

MOCA — Minimum Obstruction Clearance Altitude: same obstacle clearance, but VOR signal assured only within 22 NM of the NAVAID. Charted with an asterisk (*3400). You may fly below the MEA down to the MOCA only inside that 22 NM (IFH ch. 1; 91.177).

• MRA — Minimum Reception Altitude: lowest altitude where an off-course NAVAID can identify an intersection
• MCA — Minimum Crossing Altitude: altitude you must be at before crossing a fix where a higher MEA segment begins — start the climb early (91.177(b))
• MAA — Maximum Authorized Altitude: highest usable altitude with reliable signals
• OROCA — Off-Route Obstruction Clearance Altitude: grid altitude with a 1,000/2,000-ft buffer, but no guarantee of nav signal, radar, or communication coverage — a situational-awareness and emergency tool, not a cleared altitude (IFH ch. 1; IPH ch. 2)

The bare 91.177 minimums behind these numbers — the off-route floor itself — are covered under Task I.C.

• "Cleared HADLY ONE arrival" — lateral routing only; no descent authorized
• "…descend and maintain FL 240" — descend to the assigned altitude only, ignore charted crossing altitudes
• "Descend via the HADLY ONE arrival" — fly the lateral path and the published altitude (and speed) restrictions

A STAR connects the en route structure to the terminal area — DPs start at the pavement and climb to the en route structure; STARs start at the en route structure and never reach the pavement (IPH ch. 3).

• Non-RNAV DP — flown with ground-based NAVAIDs (or dead reckoning)
• RNAV DP — requires RNAV avionics; all public RNAV SIDs and graphic RNAV ODPs are RNAV 1, meaning total system error within ±1 NM for 95% of flight time (RNAV 2: ±2 NM). With TSO-C129 GPS, check RAIM availability before an RNAV departure
• Radar DP — ATC vectors you; annotated "RADAR REQUIRED" (IPH ch. 1)

Because radar SIDs often carry nonstandard lost-communication procedures printed on the chart. Lose the radios while being vectored on one, and ATC expects you to fly the charted lost-comm procedure — not the generic AIM/91.185 sequence. That's a detail you cannot look up while hand-flying IMC at 700 feet (IPH ch. 1).

Both jobs run at once. When you accept a SID or radar vectors, ATC is responsible for traffic separation — but you're still expected to remain vigilant in scanning for traffic when departing in visual conditions. And meteorological conditions permitting, you are required to use "see and avoid" techniques to avoid traffic, terrain, and other obstacles, IFR clearance or not (IPH ch. 1).

They show less than they seem to:

• TIS is a ground-based service delivered by Mode S data link — no ground station processing your Mode S signal, no traffic picture
• Only transponder-equipped aircraft appear at all
• Service volume is about 7 NM laterally and 3,500 feet above and below; some units display only eight intruding targets
• TCAS I and traffic alert systems issue advisories to help you visually acquire the intruder — they don't resolve the conflict

The display is an aid to see and avoid — never a replacement for it (IFH ch. 5, ch. 11).

At the point where the higher minimum applies — climb after passing the break so you reach the new MEA promptly, except where an MCA is charted: then obstructions or signal reception demand you cross the fix already at the MCA, so the climb starts early. On charts, a sideways "T" flags where the MEA, MOCA, or MAA changes at other than a NAVAID (91.177(b); IFH ch. 1).

STARs are designed around a descent gradient of about 318 ft/NM — roughly a 3° path — adjusted where crossing restrictions require. Deceleration planning allows about 1 NM per 10 knots of speed reduction. Practical use: from FL 200 crossing a fix at 11,000, you need roughly 28 NM of descent at 3° — start down late and you'll be diving or dragging speed brakes you don't have (IPH ch. 3).

Track the arrival laterally and vertically, complying with all published altitude and speed restrictions — except at BRUNO, where the ATC-issued 13,000 replaces whatever is charted — then, after BRUNO, maintain 10,000 until cleared lower. On RNAV 1 STARs you're also required to use a CDI, flight director, or autopilot in LNAV mode on the RNAV courses (IPH ch. 3).

A standard instrument approach procedure flown to a published minimum descent altitude (MDA) without approved vertical guidance (FAA-S-ACS-8C, Area VI). The lateral-only family: VOR, LOC, NDB, and the LNAV and LP lines of minima on RNAV (GPS) charts. You may use a navigator that displays advisory vertical guidance — but the approach is still flown to an MDA, honoring every stepdown altitude on the barometric altimeter (FAA-S-ACS-8C; IPH ch. 4).

At least two different non-precision approaches in simulated or actual IMC:

• At least one must include a course reversal (procedure turn, hold-in-lieu, or a TAA course reversal)
• At least one must be flown from an initial approach fix (IAF) without the autopilot and without radar vectors (yaw damper and flight director are allowed)
• One must be flown with backup or partial panel instrumentation, representing a realistic failure mode

The evaluator decides whether each approach ends in a landing or a missed approach (FAA-S-ACS-8C, Area VI Task A).

Before the final approach segment: altitude ±100 ft, heading ±10°, airspeed ±10 knots, no more than ¾-scale CDI deflection (VI.A S9).

Final approach segment: no more than ¾-scale CDI deflection, airspeed ±10 knots, and MDA +100/−0 feet to the visual descent point (VDP) or missed approach point (MAP) (VI.A S12).

Both are non-precision lines flown to an MDA.

LNAV — basic GPS lateral guidance; CDI scaling is linear (±0.3 NM on the final segment).

LP — uses WAAS accuracy to give localizer-like angular guidance: lateral sensitivity increases as you near the runway. LP is published only where terrain or obstacles prevent a vertically guided line (no LPV or LNAV/VNAV on the same chart), it is not a fail-down mode for LPV, and your WAAS navigator must be specifically approved for LP in the AFM (AIM 5-4-5).

• Within 30 NM of the airport: CDI ramps from ±5 NM en route to ±1 NM terminal sensitivity — arm the approach no later than this point
• Within 2 NM of the final approach waypoint with the approach armed: approach mode goes active and CDI ramps smoothly to ±0.3 NM
• If the approach mode is not active before the FAWP, the equipment flags — do not descend to the MDA; fly to the missed approach waypoint and execute the miss (IFH ch. 9)

Depends on the procedure (IFH ch. 1; IPH ch. 4):

• Timing from the final approach fix (FAF) — start the clock at the Maltese cross and use the chart's groundspeed/time table (30-knot increments), based on your estimated groundspeed
• NAVAID passage, when the VOR or NDB sits on the field
• A fix — DME on the course, a cross radial, or an RNAV (GPS) waypoint

On the chart it's where the solid course line ends and the dotted missed approach track begins.

A defined point on the final approach course of a non-precision straight-in approach from which a stabilized visual descent from the MDA to the runway touchdown point may be begun — charted as a V in the profile view and identified by DME or RNAV along-track distance to the MAP. You should not descend below the MDA before the VDP, and if you can't identify the VDP, fly the approach as if none were published (AIM 5-4-5).

No. The VDA is advisory only — an aid to a continuous, stabilized descent to the MDA, not procedure-derived vertical guidance. It guarantees no obstacle protection below the MDA in the visual segment; where an obstacle penetration would force a deviation from the VDA between the MDA and touchdown, the angle isn't published — the chart carries the note "Visual Segment - Obstacles" instead. Advisory glidepaths from the navigator carry the same caution — the barometric altimeter remains primary for every stepdown and for the MDA (AIM 5-4-5; IPH ch. 4).

Dive-and-drive — descend to each stepdown altitude, level off, repeat, then run level at the MDA to the MAP. It works, but multiple level-offs at low altitude invite instability.

CDFA — a constant-rate descent from the FAF that reaches the MDA near the visual descent point. A stabilized, constant-angle descent can be held from the FAF to landing, reduces CFIT exposure, and minimizes visual-illusion effects (IPH ch. 4; AC 120-108). One trap: the MDA is still an MDA — plan to level off or go missed at it, because descent below an MDA without the 91.175(c) references is never authorized.

Subtract the touchdown zone elevation (TDZE) from the FAF crossing altitude and divide by the time inbound. The IPH example: FAF at 2,000 ft MSL, TDZE 400 ft, 2 minutes inbound — 800 fpm (IPH ch. 4). Cross-check with the 300-feet-per-NM rule for an approximate 3° path: at 5 NM you should be about 1,500 ft above TDZE; at 2 NM, 600 ft (IPH ch. 4). Or just pull the rate from the descent table in the back of the TPP using the published angle and your groundspeed (AIM 5-4-5).

Configured, on speed, on the planned flight path, with a descent rate of less than 1,000 fpm — established before descending below 1,000 ft above the airport or TDZE for any straight-in instrument approach. Descent rates greater than about 1,000 fpm below 1,000 ft AGL are unacceptable in either the instrument or visual portion — a human-perception limit, not an aircraft one (IPH ch. 4). Significant speed or configuration changes during the approach degrade situational awareness and complicate the decision at the MAP.

Only when all three 91.175(c) conditions are met:

• Continuously in a position to land on the intended runway using normal maneuvers and a normal descent rate
• Flight visibility at or above the published minimum
• At least one of the ten visual references distinctly visible and identifiable

Otherwise level at the MDA to the MAP and go missed. The full reference list and the transition to landing are covered under Task VI.E.

A letter suffix means the procedure is circling-only — it's expected to end in a circling maneuver, and no straight-in minimums are published. As a general rule that happens for one of two reasons: the final approach course is aligned more than 30° from the runway centerline, or the descent gradient from the FAF to the threshold crossing height exceeds 400 ft per NM (IFH ch. 1). You may still land straight ahead if you see the runway early enough for a normal descent, but only circling minimums apply.

An ATC clearance for the RNAV procedure authorizes you to use any line of minima for which the aircraft is certified — a WAAS aircraft can take LPV or LP; a GPS-only aircraft is limited to LNAV (AIM 5-4-5). Publishing up to four lines (LPV, LNAV/VNAV, LNAV, circling) on one chart is deliberate: if WAAS service becomes unavailable, all GPS-equipped aircraft can still revert to the LNAV MDA (IPH ch. 4).

Tune, identify, monitor. Set the frequency from the chart's briefing strip, then listen to the station identifier before relying on the instrument for navigation (IFH ch. 9).

• The frequency plan itself punishes a mis-set digit: VOR assignments between 108.0 and 112.0 MHz use even tenths, avoiding conflict with localizer frequencies, which use the odd tenths in that range — one knob click can put a different facility's needle in front of you (IFH ch. 9)
• Watch the flags: an OFF flag or blank TO/FROM window means the signal is unreliable (IFH ch. 9)
• For an RNAV approach, the equivalent step is loading the procedure from the current database — building it point-to-point doesn't assure compliance, and CDI/RAIM sensitivity won't ramp down (IFH ch. 9)

No procedure turn may be made — unless ATC clears you for it — when you're:

• On a radar vector to the final approach course or fix
• Flying a timed approach from a holding fix
• On a procedure marked "No PT"

If you're unsure whether a course reversal is expected, ask before the FAF (91.175(j)).

The minimum altitude at the stepdown fix becomes your MDA. Stepdown fixes exist to authorize a lower MDA after you've passed an obstruction — no fix, no lower altitude. And if circling minimums are higher than that stepdown altitude and you're circling, circling minimums control (IFH ch. 1).

• Loss of RAIM/integrity before the FAWP: the approach mode won't go active, CDI sensitivity never ramps down — don't descend; fly to the MAWP and execute the missed approach (IFH ch. 9)
• WAAS unavailable: revert to the LNAV MDA and fly it as a lateral-only approach — GPS-only service is available nearly 100 percent of the time (IPH ch. 4)
• Loss of the navigation source entirely is a failure you must recognize and report to ATC (VI.A S5; V.A S7)

Consult the Inoperative Components or Visual Aids Table printed inside the front cover of the TPP. Example from the IFH: an approach with a malfunctioning MALSR can still be flown, but minimum visibility increases by ¼ SM (IFH ch. 1). If more than one component is inoperative, apply only the highest single penalty — the increases don't stack (IFH ch. 10). Also check chart notes: some procedures state the inoperative table doesn't apply to a specific component.

When you fly the approach — straight-in or circling — at a speed above the upper limit of your certified category. The category itself comes from 1.3 Vso (or Vref) at maximum certificated landing weight and never changes, but the minimums you use follow the speed you actually fly (IPH ch. 4). Details and the category speed bands are covered under Task VI.D.

Under Part 91 you may begin the approach regardless of reported weather — but the bottom doesn't move: if flight visibility is less than prescribed, execute the missed approach regardless of the reported visibility (IFH ch. 10; 91.175). Treat a downward trend as a decision trigger:

• Get the latest weather before the FAF and rebrief the miss — the decision at the MDA should be recognition, not deliberation
• A worsening trend makes your alternate and fuel live numbers — you must land with a 45-minute reserve (91.167); holding to await improvement or proceeding to another airport are both legitimate requests (IFH ch. 10)
• The wrong wind-and-visibility combination can make every approach at an airport unusable — know which other procedure you'd fly before you need it (IPH ch. 4)

The ACS defines it as a standard instrument approach procedure flown to a published decision altitude (DA) using approved vertical guidance (FAA-S-ACS-8C, Area VI Task B). The ILS is the classic case. An LPV or LNAV/VNAV line is technically an approach with vertical guidance (APV) in AIM terms rather than a precision approach (AIM 5-4-5), but it's flown to a DA with approved vertical guidance — from the pilot's seat an LPV "looks and flies like an ILS" (IPH ch. 4).

The localizer, the glideslope, and the outer marker — plus an inner marker where installed for CAT II/III procedures.

Authorized substitutes for the outer marker:

• A compass locator
• PAR or ASR radar
• A DME, VOR, or NDB fix authorized in the procedure
• A suitable RNAV system used with a fix identified in the procedure (91.175(k))

• Transmits on 108.10–111.95 MHz, odd tenths only; antenna at the departure end of the runway (IFH ch. 9)
• Course width is very narrow — normally 5° total, so full-scale deflection means only 2.5° off centerline; a quarter-scale deflection or less keeps you aligned with the runway
• Identified by a three-letter ident preceded by "I" (e.g., I-SGF); always positively identify it
• Usable to 18 NM from the antenna within the coverage volume (IFH ch. 9)

• Projection angle normally 2.5° to 3.5° above horizontal (up to 4° where obstacles require); it intersects the middle marker at about 200 ft and the outer marker at about 1,400 ft above runway elevation (IFH ch. 9)
• The path is only 1.4° thick full-up to full-down — needle sensitivity is high, so make small corrections early
• Radiates only on the front course — no vertical guidance on a back course
• Transmitter sits 750–1,250 ft down the runway, offset 400–600 ft from centerline (IFH ch. 9)

GS facilities inherently produce additional courses at higher vertical angles — the lowest false course occurs around 9°–12°. Getting established on one produces reversed needle indications or demands an absurd descent rate. The protection is procedural: fly the published altitudes so you intercept the glideslope from below — at charted approach altitudes the false courses are never encountered (IFH ch. 9).

• OM — blue light, low tone, continuous dashes; located 4–7 NM out, roughly where you intercept the glidepath at the published altitude
• MM — amber light, intermediate tone, alternating dots and dashes; about 3,500 ft from the threshold, glideslope about 200 ft above the touchdown zone elevation (TDZE)
• IM — white light, high tone, continuous dots; marks CAT II decision height (IFH ch. 9)

With all components operative — minimums given as decision height (DH) and runway visual range (RVR) (IPH ch. 4):

CAT I needs only an instrument-rated, current pilot and an appropriately equipped aircraft; CAT II and III require special certification for pilots, aircraft, and ground equipment (IPH ch. 4; IFH ch. 9).

Localizer performance with vertical guidance — a WAAS-based approach flown to a DA, with lateral guidance equivalent to a localizer and angular scaling that tightens toward the runway. Minimums can be as low as 200 ft HAT and ½ SM at qualifying airports — ILS-equivalent — with no ground-based transmitters, no ILS critical areas, and a signal that's actually more stable than an ILS. Requires WAAS-LPV avionics with an AFM statement supporting LPV (IPH ch. 4).

An APV line flown to a DA using approved vertical guidance — WAAS or approach-certified Baro-VNAV — with vertical and lateral integrity limits larger than a precision approach or LPV. The visibility can be higher than the LNAV line because the DA point on the vertical path sits farther from the threshold than the LNAV missed approach point (IPH ch. 4). Baro-VNAV also lives on the barometric altimeter — altimeter setting and temperature limits on the chart matter.

Establish a predetermined rate of descent at the point where vertical guidance begins — one that approximates what's needed to follow the guidance — rather than chasing the needle down. Get the rate from the rate-of-descent table in the back of the TPP using the published angle and your groundspeed (AIM 5-4-5), then hold attitude and power and make small corrections (IFH ch. 9).

Tolerances: from the final approach fix (FAF) to DA, no more than ¾-scale deflection of either the lateral or vertical indication, and airspeed ±10 knots (VI.B S12).

At DA: immediately initiate the missed approach unless the required visual references for the runway are unmistakably visible and identifiable (VI.B S13). A DA is a decision made at the altitude — the design allows a momentary descent below it while transitioning to the climb (IFH ch. 1).

The ILS reverts to a localizer approach — glideslope-out minimums are published on the chart as the S-LOC (localizer) MDA (IFH ch. 10). That only works if you briefed the LOC minimums and the timing or fix that defines the LOC MAP before you started down, so brief them every time. Recognize the failure (flags in view, needle behavior) and take appropriate action (VI.B S5); otherwise, fly the missed approach and advise ATC.

Working from the chart top-down (IPH ch. 4):

• Approach name, airport, chart date — confirm you're both on the same page
• Frequencies — localizer/NAVAID tuned and identified, comms in sequence
• Final approach course
• FAF crossing altitude and glideslope intercept altitude
• DA (or MDA) and TDZE/airport elevation
• Missed approach procedure — verbalize it so it's fresh, even when the tower will likely give instructions
• MSA, notes, required equipment (e.g., "ADF or DME required"), lighting, visibility required
• Runway length, planned configuration, and taxi expectation

By the OM, drift correction should be nailed down well enough that heading changes of no more than 2° complete the approach. As the localizer narrows toward the runway, corrections must shrink proportionately. The heaviest demand comes between the OM and MM: hold the localizer, adjust pitch for the descent rate, adjust power for airspeed, cross-check the altimeter, and prepare for the land-or-miss decision — all at once (IFH ch. 9). Small, early, trimmed corrections are the whole game.

Convert the RVR minimum to ground visibility per 91.175(h):

So a standard CAT I "RVR 2400" ILS needs ½ SM when RVR isn't available (91.175(h)).

Part 91: yes — reported weather doesn't bar you from continuing, and at the DA the 91.175(c) test is flight visibility plus the required visual references. If flight visibility is below the prescribed minimum, go missed regardless of what's reported (IFH ch. 10; 91.175(c)).

Part 121/135: crews may not proceed past the FAF unless the latest report is at or above minimums, with relief only if the report arrives after the FAF (IPH ch. 4).

Deteriorating weather is also where stabilized-approach discipline pays off: holding the parameters steady is what makes the abnormal indications of windshear stand out (IPH ch. 4). The broader divert-or-hold decision is covered under Task VI.A.

The published minimums assume every component and visual aid works. Raise them for (IFH ch. 10; 91.175(b)):

• Inoperative components or visual aids — apply the TPP Inoperative Components Table; e.g., ALSF-1 approach lights out on an ILS raises visibility by ¼ SM. Multiple failures: apply only the highest single increase.
• NOTAMs amending the procedure.
• Aircraft equipment — the authorized DA/MDA is the highest of: the procedure's, the pilot's, and the one appropriate to the equipment available and used (91.175(b)).
• Approach category — flying final faster than your category's band means the higher category's minimums.

Because at a 100-foot DH or below there's no time to assess and react using ordinary skills and equipment — so the FAA requires special certification for the pilot, the aircraft/avionics, and the ground equipment before anyone uses those minimums (IFH ch. 9; IPH ch. 4). For CAT II, the TDZ RVR system is required and controlling — no substitutions, unlike CAT I where midfield RVR can substitute when TDZ RVR is unavailable (IPH ch. 4). As a Part 91 instrument pilot you fly CAT I.

I go missed immediately, when either:

• The 91.175(c) requirements (position to land, flight visibility, visual references) are not met while I'm below the minimum descent altitude (MDA), or upon arrival at the missed approach point (MAP) (including a decision altitude (DA) where one applies) and at any time after that until touchdown; or
• During a circling maneuver at or above the MDA, an identifiable part of the airport is not distinctly visible to me — unless it's hidden only by a normal bank (91.175(e))

I also go missed whenever ATC directs it, and whenever I reject a landing for any reason — traffic on the runway, windshear, or an approach that comes unstabilized (IFH ch. 10; IPH ch. 4).

Yes — a clearance for an instrument approach procedure includes a clearance to fly the published missed approach procedure, unless ATC instructs otherwise (AIM 5-4-21; IPH ch. 4). That's why I brief it before every approach: when I need it, my workload is at its maximum.

In order (IFH ch. 10; VI.C S1–S4):

1. Pitch and power — climb attitude, climb power
2. Configure — clean up per the manufacturer's procedure, verify a positive rate of climb, accelerate to the appropriate speed ±10 knots
3. Navigate — fly the published (or ATC-issued) missed approach track
4. Communicate — advise ATC the missed approach is underway and request further clearance
5. Checklist — complete the go-around/missed approach items

I aviate first: I establish the climb before anyone hears from me.

Unless otherwise cleared, I continue to fly the approach as charted to the MAP at or above the MDA or DA — then begin any turning maneuver (AIM 5-4-21; IFH ch. 10). Turn containment on the missed is designed from the MAP; an abnormally early turn gets no protection. I may climb early, but I watch for published altitude restrictions between the final approach fix (FAF) and MAP that protect overlying procedures — some charts require staying down until a fix (IPH ch. 4).

A climb gradient of at least 200 ft per NM, beginning at the MAP at the MDA/DA — unless a higher gradient is published in the notes (AIM 5-4-21). Two traps: gradient is feet per mile, so a higher groundspeed demands a higher rate in fpm (conversion table on page D1 of the TPP); and if I can't meet a published non-standard gradient, I say so — I advise ATC or use the charted alternative, often a separate procedure with higher minimums and a standard gradient (AIM 5-4-21; IPH ch. 4).

The published miss doesn't protect me — obstacle clearance is assured only from the MAP at or above the MDA/DA (AIM 5-4-21).

1. I contact ATC as soon as possible for an amended clearance
2. If unable, I attempt to re-intercept a published segment of the missed approach and comply with its routing and altitudes
3. If that's no longer appropriate, I consider maintaining visual conditions and reattempting the landing, or a circle-climb over the airport (AIM 5-4-21; IPH ch. 4)

I think through this scenario before starting the approach.

I request clearance for a specific action:

• Another approach
• The holding fix or clearance limit
• Diversion to my alternate (AIM 5-4-21)

I drive the decision with fuel and weather: what changed, and will it be different next time? I remember my planning reserve — fuel to destination, then alternate, then 45 minutes at normal cruise (91.167) — and I don't burn it holding for weather that isn't improving. The missed approach track typically ends at a holding fix that's often also an IAF, so a second attempt doesn't require backtracking (IPH ch. 4).

Airspeed ±10 knots; heading, course, or bearing ±10°; altitude ±100 ft (VI.C S7).

Also expected:

• Prompt initiation and report to ATC
• Proper configuration and positive rate
• Compliance with the published or alternate procedure
• Advising ATC if unable to meet a clearance, restriction, or climb gradient (VI.C S1–S6)

I execute the missed approach procedure without delay and contact ATC when able (AIM 5-4-21). I climb to a safe altitude before proceeding off the published missed approach — abandoning it before reaching the published altitude may not provide terrain clearance, and additional climb in the hold may be required before heading to an IAF or the alternate (AIM 5-4-21).

On every chart, the MAP is where the solid course line ends and the dotted missed approach line begins in both plan and profile views (IPH ch. 4).

• Precision/APV: reaching the DA on the glideslope/glidepath
• On-field VOR or NDB: passage of the NAVAID
• Timed: a distance from the FAF, flown as time from the groundspeed table
• Fix-based: LOC/VOR course plus DME, a cross radial, or an RNAV waypoint

Icons in the profile view give the initial vertical and lateral missed approach instructions (IPH ch. 4).

The receiver does not sequence past the missed approach waypoint on its own — I must activate the missed approach (IFH ch. 9). Until I do, the unit displays an extension of the final approach course with along-track distance increasing from the MAWP.

Two cautions: activating the miss before the MAWP snaps CDI sensitivity back to terminal (±1 NM) immediately while I'm still navigating to the MAWP, so turns shouldn't begin before the MAWP; and if the first missed approach leg is a course rather than direct-to-a-waypoint, I must also set the course (IFH ch. 9).

I know my box's exact activation procedure cold.

A preplanned backup for when the primary missed approach NAVAID is unavailable. The textual instructions are not published on the chart (only the alternate holding pattern is depicted); the procedure is implemented by NOTAM — at which point it becomes mandatory — or issued by ATC, such as when the NAVAID fails during my approach (AIM 5-4-21).

If ATC issues it after I've begun the approach and it requires equipment I don't have, I may reject it.

If issued before the approach, I must:

• Accept the whole package
• Request a different approach
• Coordinate something else (AIM 5-4-21)

An instrument approach that ends in visual maneuvering to a runway that doesn't meet straight-in criteria. Circling minimums apply when it's necessary to circle the airport or maneuver for landing, or when no straight-in minimums are published (IFH ch. 10). Circling-only procedures (letter suffix — "VOR-A") generally exist because the final approach course is aligned more than 30° from the runway, or the descent gradient exceeds 400 ft/NM from FAF to threshold (IFH ch. 1). You'll also circle when winds favor a different runway than the approach serves.

A grouping by speed — Vref, or if not specified, 1.3 Vso at maximum certificated landing weight (IPH ch. 4):

• Category A — less than 91 knots
• Category B — 91 to less than 121 knots
• Category C — 121 to less than 141 knots
• Category D — 141 to less than 166 knots
• Category E — 166 knots or more

Speeds are indicated airspeeds. The certified category is permanent — you can never use a slower category's minimums — but flying faster than your category's band means using the higher category's minimums (IPH ch. 4).

Arcs from each runway end, radius by category (IPH ch. 4):

• Category A — 1.3 NM
• Category B — 1.5 NM
• Category C — 1.7 NM
• Category D — 2.3 NM
• Category E — 4.5 NM

Procedures developed after late 2012 use expanded radii that also grow with the height of the circling minimum descent altitude (MDA) (true airspeed increases with altitude) — identified by the "negative C" symbol on the circling line of minima, with the radii table on page B2 of the TPP (AIM 5-4-20). The expanded airspace exists so you can maneuver instead of forcing a high descent rate (IPH ch. 4).

A minimum of 300 feet within the protected area (IFH ch. 10; IPH ch. 4). Below the MDA it's entirely see and avoid — and part of the circling area may be procedurally cut off ("Circling NA E of RWY 17-35") because of obstacles (AIM 5-4-20). Stray outside the protected radii and there's no guaranteed clearance at all.

Remain at or above the circling MDA until the aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers (IPH ch. 4; 91.175(c)) — in practice, roughly where you'd start descending from a normal pattern. If the ceiling allows, circle above the minimums at something near VFR pattern altitude — the maneuvering is safer and the runway picture more familiar (IFH ch. 10).

Immediately execute the missed approach — required whenever an identifiable part of the airport is not distinctly visible during a circling maneuver at or above the MDA, unless it's hidden only by a normal bank (91.175(e)(2)). Make an initial climbing turn toward the landing runway, and continue turning until established on the missed approach course (AIM 5-4-21; IFH ch. 10). The turn direction depends on where you are in the circle when visual reference is lost — which is why you brief this geometry before the approach.

• Procedural sector cutoffs: "Circling NA" for a named sector, driven by obstacles (AIM 5-4-20)
• Where obstacles penetrate the visual-area surfaces and are unlighted, night operations may be prohibited outright — "Procedure NA at Night" — and circling may be permitted at night only if penetrating obstacles are marked and lighted (IPH ch. 4)
• Some restrictions are restored only by an operating VGSI (AIM 5-4-5)

Read the notes box — at night the notes are the terrain picture.

• Arrive at the MDA (or preselected circling altitude above it) prior to the missed approach point (MAP), with a stabilized approach in the landing configuration (VI.D S4)
• ±10 knots, heading/track ±10°, altitude +100/−0 ft until descending below the MDA or preselected circling altitude (VI.D S5)
• Maneuver visually to a base or downwind appropriate to the runway (VI.D S6)
• Land in the first one-third of the runway, without excessive maneuvering and without exceeding 30° of bank (VI.D S8)

The IPH calls circling one of the most challenging maneuvers in the NAS: low altitude, day or night, often with precipitation degrading visibility and depth perception, and usually to a runway with no electronic guidance for the descent from the circling MDA (IPH ch. 4). Stack on marginal visibility, unfamiliar geometry, and the temptation to tighten a turn to the runway, and the outcomes are stall/spin or CFIT — the ACS names low-altitude maneuvering risk explicitly (VI.D R6). Mitigate with personal minimums well above the circling MDA, and a firm no-visual-no-circle rule at night.

• Pattern A — final approach course intersects the runway at less than 90° and you see the runway early enough to establish a base leg: fly onto base
• Pattern B — runway appears too late for pattern A: circle over/around to downwind
• Pattern C — landing opposite the final approach direction, runway sighted in time to turn downwind: fly the downwind past the numbers, then base
• Pattern D — landing opposite but runway sighted too late for a downwind turn: fly beyond the runway before turning

Whatever the pattern, stay within the protected radii — and choose based on your own capabilities, aircraft performance, wind, ceiling, airport layout, and ATC instructions (IFH ch. 10).

Because by the time you start maneuvering you're usually beyond the MAP — the point the published miss is built from. You're clear of obstacles at or above the MDA inside the circling area, but simply joining the missed approach ground track may not give vertical clearance once you exit the circling area; additional climb inside the circling area may be required before joining the track (AIM 5-4-20). Hence the technique: climbing turn toward the landing runway, then intercept the missed approach course (AIM 5-4-21).

Category B. Minimums follow the speed you actually fly: an aircraft in Category A circling to land at a speed in excess of 91 knots must use Category B minimums (IFH ch. 1; IPH ch. 4). The protected radii are built for the category's speed — carry Category A minimums through a Category B groundspeed turn and you can swing outside protected airspace. Situations that push speed up: gusty winds, no-flap or reduced-flap approaches, icing (IPH ch. 4).

• Configure for landing and slow to circling speed before the MDA level-off — arrive at the MDA before the MAP, not diving at it (VI.D S4)
• Fly deliberate, pattern-like geometry: downwind spacing you know, bank 30° or less, no button-hook turns (VI.D S8)
• Account for turbulence and windshear in speed and spacing (VI.D S1); a tailwind on downwind steals spacing fast
• From the roll-out onto final: normal descent point, normal rate — if you'd need an abnormal maneuver or excessive descent to make the runway, go missed (IPH ch. 4; 91.175)

Decide how each system will be used in the approach briefing:

• Autopilot: the AFM defines its procedures and limitations, and the lowest altitude it may stay engaged is aircraft-specific; plan to be hand-flying by the MDA level-off, since an autopilot still coupled to the final approach course will fly you away from your visual pattern (IPH ch. 4)
• Navigator: leave it on the approach — the GPS does not sequence past the MAWP automatically, so missed approach guidance is one deliberate activation away if you lose the runway mid-circle (IFH ch. 9)
• Missed approach: normally hand flown with flight director guidance; re-engage automation once established on the missed approach course (IPH ch. 4)

To leave the decision altitude (DA) or minimum descent altitude (MDA) for the runway:

1. The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers
2. The flight visibility is not less than the visibility prescribed for the approach
3. At least one of the required visual references for the intended runway is distinctly visible and identifiable

All three, the whole way down — lose any one below the minimums and the missed approach is mandatory (91.175(c), (e)).

• The approach light system (with a catch — see the next card)
• The threshold, threshold markings, or threshold lights
• The runway end identifier lights (REIL)
• The visual glideslope indicator (VASI/PAPI)
• The touchdown zone or TDZ markings, or TDZ lights
• The runway or runway markings
• The runway lights

Ten references; nine are runway-environment cues, one is the light system leading to it (91.175(c)(3)).

With only the approach light system in sight, I can descend to — but not below — 100 ft above the touchdown zone elevation, unless the red terminating bars or red side row bars are also distinctly visible and identifiable (91.175(c)(3)(i)). No red bars in sight by 100 ft above TDZE, and nothing else from the list visible: I go missed.

Flight visibility — what I observe from the cockpit — controls. Only the pilot can determine whether flight visibility meets the landing requirement: if it does, I continue to land even if reported visibility is lower; if it doesn't, I execute the missed approach regardless of what's being reported (IFH ch. 10; 91.175(c)(2)). Landing when flight visibility is below the prescribed minimum violates 91.175(d) — a separate prohibition from the descent rule.

The ALS penetrates the murk far enough from touchdown to give directional, distance, and glidepath information for the visual transition (IFH ch. 9). Common systems: ALSF-1 and ALSF-2, SSALR/MALSR and MALSF, and ODALS — many large airports add the high-intensity sequenced flashers ("the rabbit"), a ball of light running toward the runway twice per second (IFH ch. 9). I know my destination's system before the approach — identification at minimums must be instantaneous (IFH ch. 9).

REIL: a pair of synchronized flashing lights at the threshold corners for rapid, positive identification of the approach end (IFH ch. 9).

VASI: red/white light bars projecting a visual glidepath that provides safe obstruction clearance within the approach zone; on ILS runways the VASI angle normally coincides with the electronic glideslope. On glidepath: near bars white, far bars red. All red — I'm below; a safe obstruction clearance might not exist (IFH ch. 9). Both are 91.175(c)(3) references.

I keep flying the instruments while sampling outside, rather than abandoning the scan at the first ground contact — one of the most challenging moments of the approach, especially single-pilot (IPH ch. 4). Cautions:

• Shallow fog — I may see the runway from above, then lose the visual flare cues in the fog layer; I stay ready to go around
• Approaches with vertical guidance arrive stabilized, making the transition safer — I use the glidepath to touchdown even when visual
• I use the VGSI to confirm I'm positioned for a stabilized descent (AIM 5-4-5)

Very little. There is no implicit obstacle protection from the MDA/DA to the touchdown point — the visual segment is evaluated, but obstacles are allowed to penetrate it; seeing and avoiding them is my job (AIM 5-4-5). I fly the visual glidepath, not below it: some charts require "remain on or above VGSI glidepath until threshold" (AIM 5-4-5). I aim to cross the threshold at a nominal 50 ft (IPH ch. 4) — the typical charted TCH is 30–50 ft (IFH ch. 1). If I duck under, the clearance margins go with me.

Whenever a normal landing is no longer assured: the approach becomes unstabilized, the runway is occupied, windshear, or I'd need excessive maneuvering to reach the touchdown zone. A missed approach is required upon a rejected landing for any reason (IPH ch. 4) — and 91.175(e) applies until touchdown, so losing the required references or visibility in the flare still means I go around. Configuration and checklist discipline (VI.E S3) keep the go-around clean: I know my airplane's balked-landing procedure cold.

In low visibility the first cue is usually the sequenced flashers and approach light bars, then threshold cues, then runway texture. As the threshold approaches, the visual glidepath separates into individual lights — at that point I continue by reference to the touchdown zone markers (IFH ch. 9). The approach divides into two stages: the instrument stage on radio/GPS guidance, and the visual stage where ground contact provides accuracy — the most critical moment is the land-or-miss decision that joins them (IFH ch. 9). I call out what I see against what I briefed: expected lighting type, TDZ markings, runway length remaining.

Straight-in: I arrive on centerline, stabilized, usually on a 3° path — hold configuration, track the visual glidepath from DA/MDA or the VDP, and land in the touchdown zone at a normal descent rate (VI.B S14/S15; IPH ch. 4).

From a circle: I roll out of a visual pattern I built myself — the stabilized-approach gates still apply from the final turn: landing configuration, target speed, normal descent point. I land within the first one-third of the runway without excessive maneuvering (VI.D S8). Either way, the environmental factors — wind, windshear, runway surface, NOTAMs, wake turbulence — come from ATIS/ATC advisories and my own briefing (VI.E S2).

Three habits (VI.E S1, S3–S5):

• Transition at a defined point — DA/DH, MDA, or the VDP — to visual flight that allows safe maneuvering and a normal landing; no duck-unders, no salvage dives from the MAP
• Checklist complete — landing configuration verified before the visual segment gets busy
• Positive control to touchdown — I fly the airplane through the flare and rollout; the approach isn't over until taxi speed

Single-pilot resource management is graded here too: I brief the lighting, the go-around trigger points, and the balked-landing procedure before the FAF, so the decision at minimums is recognition, not deliberation (VI.E S5; IPH ch. 4).

• Try the last assigned frequency again, then the previously assigned frequency
• Try any other known frequencies for the facility — preferably the next sector's — and try calling an FSS
• Monitor your NAVAIDs — ATC may transmit instructions over a VOR, VORTAC, NDB, or localizer voice channel
• If only your transmitter failed, listen for ATC instructions on any operational receiver, including the nav radios
• Squawk 7600 and keep trying to re-establish contact (IFH ch. 11; IPH ch. 2)

Your data block on the controller's scope flashes RDOF (radio failure), alerting the controller that you have a two-way radio communications failure (IPH ch. 2). ATC then knows to apply lost-comm expectations to your target while you continue trying to re-establish contact.

Continue the flight under VFR and land as soon as practicable (91.185(b)). This rule applies whether the failure occurs in VFR conditions or you encounter them afterward — it takes priority over the IFR route/altitude procedures.

"Practicable" is not "as soon as possible" — you keep the prerogative of judgment and are not required to land at an unauthorized or unsuitable airport (IPH ch. 2).

7,000 — the highest of the assigned altitude (5,000), the minimum IFR altitude (6,000), and the expected altitude (7,000) for the route segment being flown (91.185(c)(2)). Re-evaluate at every segment: the answer can change as the MEA changes.

• Begin the climb to the higher MEA when you reach the fix where the MEA rises
• If that fix has a published MCA, start the climb early enough to cross the fix at or above the MCA
• When a later segment's MEA drops back below your assigned/expected altitude, descend at the fix where the MEA decreases, down to the last assigned altitude or the altitude ATC advised to expect (IPH ch. 2)

Commence descent, or descent and approach, as close as possible to the expect-further-clearance (EFC) time if you received one. If you did not, begin as close as possible to your ETA as calculated from the filed — or amended with ATC — estimated time en route (91.185(c)(3)(i)).

• Leave the clearance limit at the EFC time if one was received
• If none was received, leave it upon arrival over it
• Then proceed to a fix from which an approach begins and commence descent, or descent and approach, as close as possible to the ETA from your filed or amended ETE (91.185(c)(3)(ii))

• Your airplane: a failed transmitter, receiver, or both — and an electrical charging-system failure, which gives you roughly 30–40 minutes of battery before everything electrical quits (IFH ch. 11)
• The ground: an ARTCC radio frequency outage — the backup transmitter is usually in service within 60 seconds, so wait at least one minute before concluding the frequency has actually failed (IPH ch. 2)

Because complete failures are rare, troubleshoot before you assume — a partial failure (transmitter only) still lets you receive instructions (IPH ch. 2).

• The 91.185 procedures apply "unless otherwise authorized by ATC" (91.185(a))
• If you're in — or encounter — VFR conditions, you must continue under VFR and land as soon as practicable (91.185(b))
• And as PIC you retain emergency authority to deviate from any rule to the extent required to meet the emergency (91.3)

The regulation's purpose is to keep you predictable — extended no-radio IFR operation adversely affects other users of the airspace (IPH ch. 2).

No — commence the descent and approach as close as possible to your ETA as calculated from the filed or amended ETE (91.185(c)(3)(i)). Hold at the fix until then. ATC is protecting the approach environment based on when the system expects you, not when you happen to show up.

1. Wait at least one minute — backup transmitter switchover seldom takes more than 60 seconds (IPH ch. 2)
2. If you can't raise the new sector, re-contact the transferring controller for an alternate frequency or instructions
3. If the failure happens after contact was established, try any other known ARTCC frequency — preferably the next sector's — and ask for instructions
4. Failing that, request communication instructions from the FSS appropriate to your route — FSS relay is faster than company radio because FSS has direct interphone lines to the responsible ARTCC sector (IPH ch. 2)

Once the charging system fails you have roughly 30–40 minutes of battery, and possibly less — never continue the flight once the charging system has failed; land at the nearest suitable airport (IFH ch. 11).

• Load-shed: turn off or pull breakers on all non-essential electrical equipment
• Tell ATC now, while you still can — advise them of the situation and the impending electrical failure (IFH ch. 11)
• Plan for the panel you'll have left; in a glass cockpit this failure also takes your displays (covered under Task VII.D)

Separation in IMC depends on ATC predicting your path. The primary objective of the lost-comm rules is to preclude extended IFR no-radio operations, because a silent, unpredictable airplane adversely affects every other user of the airspace (IPH ch. 2). Fly AVEF and the highest-of-three altitude, arrive on your ETA, and the system can work around you. The sanctioned "improvisations" are exactly three: ATC authorization, VFR conditions, or a genuine emergency (91.185, 91.3).

Positive aircraft control — promptly recognize the failure and keep flying the airplane (IR.VII.B.S1). On instruments that means the scan does not stop: distractions, task prioritization, loss of situational awareness, and disorientation during the failure drill are listed risks of this Task (IR.VII.B.R4). Handle the engine only as fast as you can do it without letting attitude, heading, or airspeed get away.

1. Set the engine controls and reduce drag
2. Identify the inoperative engine
3. Verify it
4. Simulate feathering the propeller on the inoperative engine — the evaluator then establishes zero thrust
5. Establish the best engine-inoperative airspeed and trim

Then verify the securing checklist, try to determine and resolve the cause, and monitor the operating engine (IR.VII.B.S5–S7). The exact control order comes from your POH/AFM.

A power setting on the "failed" engine that simulates the drag of a feathered propeller without shutting the engine down — you simulate the feather; the evaluator then sets zero thrust (IR.VII.B.S2). Actually securing an engine in flight — let alone in IMC — trades a training benefit for a real emergency, so the evaluator must brief the manufacturer-recommended methods for simulating engine failure during the preflight briefing (FAA-S-ACS-8C, Appendix 2, Multiengine Considerations).

The best engine-inoperative airspeed, established and trimmed for (IR.VII.B.S3). On the airspeed indicator, the blue radial line marks the airspeed for best single-engine rate of climb at gross weight and sea level (IFH ch. 5) — your POH/AFM gives the numbers for other weights and altitudes.

• Altitude ±100 feet — or minimum sink rate if the airplane can't hold altitude
• Airspeed ±10 knots
• Heading ±10°

Note the "minimum sink" escape hatch: the standard recognizes that a light twin on one engine may be unable to maintain altitude (IR.VII.B.R2).

• Fly the best engine-inoperative airspeed for minimum sink (IR.VII.B.S3, S8)
• Assess performance capability and decide an appropriate action to ensure a safe landing (IR.VII.B.S9)
• Tell ATC: under IFR you must report when unable to climb or descend at least 500 fpm, and report any information relating to the safety of flight (IPH ch. 2) — an engine failure and an OEI ceiling below the MEA certainly qualify

Because an airplane that can't climb or maintain altitude on one engine (IR.VII.B.R2) will eventually be maneuvering low and slow with thin margins — the setup for a stall, spin, or controlled flight into terrain. The mitigations are built into the Task:

• Hold the best engine-inoperative airspeed (IR.VII.B.S3)
• Stay trimmed and within the aircraft's operating limitations (S10)
• Assess performance capability and decide on a safe landing early (S9) — while you still have altitude to spend on the decision, not after the terrain has closed the options

The approach-phase version of this risk is covered under Task VII.C.

• Verify the prescribed checklist procedures used for securing the engine — high-workload memory items get reviewed against the checklist once conditions permit (FAA-S-ACS-8C, Appendix 2)
• Attempt to determine and resolve the reason for the failure
• Monitor engine functions on the operating engine and adjust as necessary
• Assess performance and commit to a plan for a safe landing

One engine is now doing all the work from whatever tanks feed it — you must know your fuel system's single-engine procedures cold from the POH/AFM before you need them: which tanks feed the operating engine, how to keep it fed, and what the emergency checklist says about fuel selectors and pumps. Brief this on the ground; on instruments you won't have spare attention to reason it out.

Yes — your certificate will bear the limitation "Multiengine Limited to VFR Only." Test in a multiengine airplane and instrument privileges are automatically conferred on the single-engine rating. Removing the VFR-only limitation later — at the private or commercial pilot certificate level — requires satisfactorily performing Tasks VII.B and VII.C in a multiengine airplane with a manufacturer's published VMC (FAA-S-ACS-8C, Appendix 1).

With your airplane's numbers, not a generic one: the standard is the control combination recommended by the manufacturer, or as required for best performance, trimmed off so you can keep flying the scan (IR.VII.B.S4). Follow up with why trim matters on instruments — untrimmed control pressure destroys the light touch instrument corrections require and steals attention from the cross-check (IFH ch. 7).

Because OEI, performance margins are thin (IR.VII.B.R2) and every configuration item is a drag decision. The S2 flow opens with set the engine controls and reduce drag, and simulating the feather removes the failed propeller's drag (IR.VII.B.S2) — but the ACS leaves the specifics to your airplane: know from the POH/AFM exactly which items your drag-reduction step covers (flap and gear positions and the rest of the manufacturer's OEI configuration) and in what order. Then keep the airplane configured and flown as recommended by the manufacturer, or as required to maintain best performance, trimmed (IR.VII.B.S4). Configuration on the single-engine approach is covered under Task VII.C.

In a typical twin, no — the instrument pneumatic system uses two engine-driven air pumps feeding a manifold check valve. If either engine or pump quits, the check valve isolates the failed side and the instruments are driven by air from the operating system (IFH ch. 5). Verify what your airplane actually has: consult the POH/AFM for the power source of every instrument so you know what to expect when a failure occurs (IFH ch. 5).

• The multiengine airplane must have a manufacturer's published VMC — unless your certificate has a center-thrust limitation (FAA-S-ACS-8C, Appendix 3)
• The evaluator must discuss the methods for simulating an engine failure in accordance with the manufacturer's recommended procedures during the preflight briefing (Appendix 2, Multiengine Considerations)
• On an IPC, Area VII Tasks B, C, and D are required — B and C in multiengine airplanes only, and the multiengine Tasks must be flown in an aircraft or a Level B/C/D FFS, not an AATD (Appendix 1)

1. Recognize promptly and maintain positive aircraft control (IR.VII.C.S1) — the scan doesn't stop
2. Run the failure flow: engine controls, drag, identify, verify, simulate feather; evaluator sets zero thrust (IR.VII.C.S2 — covered in detail under Task VII.B)
3. Follow the manufacturer's emergency procedures and complete the appropriate checklist (IR.VII.C.S4)
4. Tell ATC — an engine failure is information relating to the safety of flight, a required IFR report (IPH ch. 2) — then request and follow a clearance for an instrument approach (IR.VII.C.S6)

No. The single-engine approach carries the same numbers:

• Altitude ±100 feet (or minimum sink rate if applicable), airspeed ±10 knots, heading ±10° (IR.VII.C.S7)
• On the final approach segment: lateral — and vertical, as applicable — guidance within ¾-scale deflection (IR.VII.C.S9)
• If circling, comply with the published criteria for your approach category (IR.VII.C.S11)

A rate of descent that ensures arrival at the minimum descent altitude (MDA) or decision altitude/height (DA/DH) with the airplane in a position from which a descent to a landing on the intended runway can be made — straight-in or circling as appropriate. In other words: no diving at minimums, no arriving high and fast with nowhere to go — especially when the go-around option is compromised (IR.VII.C.R6).

Use the flight controls and configuration as recommended by the manufacturer or as required for best performance, trimmed (IR.VII.C.S3), following the POH/AFM's OEI approach procedure. Configuration is a listed risk because every notch of flaps and the landing gear add drag you may not be able to afford on one engine (see IR.VII.B.R2 — inability to climb or maintain altitude). Brief before the approach exactly where you will extend gear and flaps — don't decide it at 500 feet in the soup.

A light twin on one engine may be unable to climb or maintain altitude (IR.VII.B.R2), so a low-altitude go-around invites loss of control or CFIT (IR.VII.C.R4). Manage it before it happens:

• Fly the descent so you arrive at MDA/DA in a position to land (IR.VII.C.S8)
• Brief a commit point and your plan at minimums before starting the approach
• Assess performance capability early and pick an appropriate action for a safe landing (IR.VII.B.S9) — which may mean choosing a longer runway or better weather while you still have altitude

A lot — if you tell them. ATC may offer radar approach options to aircraft in distress regardless of weather (IPH ch. 4): a PAR (precision approach radar — vertical and lateral guidance plus range, the most precise radar approach available) or an ASR (surveillance — heading and range, with recommended altitudes available on request). Radar approach details are covered under Task VII.D.

Fly the published or recommended immediate-action memory items first, then review the checklist once conditions permit — the ACS explicitly recognizes that reading a checklist can be impractical or unsafe in the moment, and evaluates you on that judgment (FAA-S-ACS-8C, Appendix 2, Use of Checklists). The Task still ends with completing the appropriate checklists after landing (IR.VII.C.S13).

The operating engine and aircraft systems — adjusting as necessary. Everything is riding on that engine: watch its indications, keep it fed (fuel management, IR.VII.B.R5), and stay within the aircraft's operating limitations (IR.VII.C.S10).

The ACS allows either: arrive at minimums positioned to land straight in or circling as appropriate (IR.VII.C.S8), and circling must honor the published criteria for your approach category (IR.VII.C.S11). Risk management favors the option that minimizes low-altitude maneuvering — maneuvering close to the ground with an inoperative engine is precisely the stall/spin/CFIT risk the Task lists (IR.VII.C.R4). Be ready to justify your choice in terms of runway, weather, and OEI performance.

The instruments. Failure handling, ATC coordination, and configuration changes are all competing with the scan, and unusual attitudes result from confusion, preoccupation with flight-deck duties, and carelessness in cross-checking (IFH ch. 7). The discipline: aviate first — make engine and configuration changes at a rate your cross-check can absorb, and let the evaluator see deliberate task prioritization (IR.VII.C.R5, S14).

• Multiengine tests only; the airplane needs a manufacturer's published VMC unless your certificate carries a center-thrust limitation (FAA-S-ACS-8C, Appendix 1 and Appendix 3)
• The evaluator must brief the methods for simulating engine failure per the manufacturer's recommendations before flight (Appendix 2, Multiengine Considerations)
• Required on a multiengine IPC, and it must be flown in an aircraft or Level B/C/D FFS — not an AATD (Appendix 1)
• Non-amphibious seaplanes: the Task applies only when there's immediate access to an instrument approach to a waterway (Task note)

A warning indicator or flag, or an inconsistency between the attitude indicator and the supporting performance instruments. When something disagrees, expedite the cross-check and include all flight instruments — the problem may be a single instrument or a system failure taking out several at once (IFH ch. 11).

Immediately compare the attitude indicator against the rate-of-turn indicator and the VSI. Besides giving pitch and bank information, that comparison cross-checks the suction/pressure system (AI) against the electrical system (turn indicator) and the static system (VSI) — identify the failed component, then fly the remaining functional instruments (IFH ch. 11).

• It takes out the attitude indicator and heading indicator — and they can fail progressively: as the gyros spin down they wander, indications you can easily misinterpret if you fail to see the OFF or failed flags
• Wandering gyros can feed incorrect movement or erroneous indications to an autopilot or flight director
• Many small aircraft have no vacuum failure warning, so the pilot must monitor the vacuum/pressure gauge

An unnoticed failure can lead you into an unusual attitude that then demands a partial-panel recovery (IFH ch. 11).

A static system problem affects the ASI, altimeter, and VSI (IFH ch. 11).

• Select the alternate static source — location and operation per the POH/AFM
• With no alternate source, in an unpressurized airplane, you can break the glass on the VSI — it isn't required for instrument flight — giving the altimeter and ASI a static source, though this can introduce additional instrument errors (IFH ch. 11)

The system reverts to reversionary mode: the multi-function display (MFD) presents the primary flight display (PFD) instruments combined with the engine indicating system (IFH ch. 11). If instead the attitude and heading reference system (AHRS) fails, you're on partial panel — every maneuver except the instrument takeoff can be flown that way (IFH ch. 7). Either way you also have the standby instruments: standby attitude indicator, altimeter, ASI, and the magnetic compass (IFH ch. 11).

Glass panels power the AHRS, air data computer, PFD, and engine indications electrically — so a charging-system failure that was an abnormality in a round-dial airplane is an emergency in a technically advanced one (IFH ch. 11).

• Main battery: roughly 30–40 minutes of useful voltage, an approximation you must not lean on
• The standby battery (switch must be ARMed) comes online as the main battery depletes and powers the essential bus: AHRS, ADC, PFD, Nav 1, Com 1, standby indicator light
• Load-shed and land as soon as practical — never continue a flight after the charging system fails (IFH ch. 11)

Yes. Under IFR in controlled airspace you must report any malfunction of navigational, approach, or communication equipment as soon as practical (91.187), including:

• Aircraft ID
• Equipment affected
• Degree your IFR capability is impaired
• Nature and extent of assistance desired

Advise ATC or the evaluator if you're unable to comply with a clearance (IR.VII.D.S1), and declare an emergency before the situation deteriorates beyond your ability to recover (IFH ch. 11).

Two tools (IFH ch. 7):

• Timed turns — at standard rate, 3° per second; bank for standard rate ≈ 15 percent of TAS (divide airspeed by 10, add half: 100 knots → 15° of bank)
• Compass turns — usable, but only if you respect the magnetic compass's lead/lag errors (next card)

With 15°–18° of bank, lead or lag approximately equals your latitude (IFH ch. 7):

• Turning to north: the compass lags — lead the roll-out by your latitude plus normal roll-out lead
• Turning to south: the compass leads — turn past south by your latitude minus roll-out lead
• Turning to east or west from north: lead by about 10°–12°; from south: about 5°
• On east/west headings, acceleration indicates a turn toward north, deceleration toward south; on north/south headings, speed changes cause no error (IFH ch. 7)

The altimeter becomes your primary pitch reference, with the VSI backing it up (IFH ch. 7).

• First stop the needle movement with a smooth input, then pitch back toward the entry altitude
• Target a vertical speed about double the altitude deviation — 200 feet off, correct at 400 fpm — capped at an optimum 500–1,000 fpm
• Avoid abrupt control movements; overcontrolling turns one deviation into a series of them (IFH ch. 7)

A radar approach for when your directional gyro or stabilized compass is inoperative or inaccurate: advise ATC and request a no-gyro vector or approach. The controller says "turn right … stop turn" — you make standard-rate turns, executing immediately on each instruction, and switch to half standard rate once turned onto final (IFH ch. 10; IPH ch. 4).

Complete a nonprecision instrument approach without the use of the primary flight instruments, flown to the same skill elements as the nonprecision approach Task (Area VI, Task A) — while using the secondary/standby displays properly (IR.VII.D.R1) and keeping ATC in the loop (IR.VII.D.S1).

1. Attempt to restore it — check the power source, switch to a backup or alternate system, reset the instrument if possible (IFH ch. 11)
2. Cover the failed instruments — covering them may enhance your ability to maintain aircraft control and navigate (IFH ch. 11)
3. Advise ATC, and if necessary declare an emergency before things deteriorate (IFH ch. 11, 91.187)

Knowing what to check requires knowing what powers what: consult the POH/AFM for the power source of every instrument before you ever need the answer in flight (IFH ch. 5).

Unusual attitudes result from instrument failure, confusion, preoccupation, and errors in interpretation among other causes (IFH ch. 7) — a dying gyro that wanders while its failed flags go unnoticed is a machine for producing exactly that confusion (IFH ch. 11). During recovery, remember the attitude indicator itself may not be trustworthy: don't depend on a spillable-type AI whose limits may have been exceeded (IFH ch. 7). Recover on the instruments you've verified.

One recommended technique: switch the MASTER side off to take the main battery offline — with the standby battery ARMed, it comes online to power the essential bus. Using the standby battery first reserves the main battery for the approach, when you'll want flaps, gear, and lights. Don't count on any power after the standby battery is exhausted — the flight deck may go completely dark, and navigation falls back to pilotage/dead reckoning unless you carry a handheld with GPS (IFH ch. 11).

An airport surveillance radar approach gives heading and range only — the controller can also advise recommended altitudes each mile on final, if you ask (IFH ch. 10). Design protections (IPH ch. 4):

• Final approach course aligned with the runway centerline (straight-in) or the airport center (circling)
• 250 feet minimum obstacle clearance in the final approach area
• Flat descent gradients — optimally 150 feet per mile, never exceeding 300

ASR approaches are typically approved only for ATC operational needs or unusual/emergency situations — a partial-panel day qualifies (IPH ch. 4).

Preflight: pay particular attention to the alternator belt, antennas, static wicks, anti-ice equipment, pitot tube, and static ports.

Taxi: verify flight instrument operation and accuracy.

Run-up: confirm the pneumatic system reads within acceptable parameters.

All systems should be verified operational before departing into IFR conditions (IFH ch. 11) — and in a glass airplane, the standby battery must be armed before departure for its automatic protection to work (IFH ch. 11).

Anything the flight caused or revealed — especially things that only show up under IFR workload:

• Nav and comm behavior: intermittent flags, a glideslope that dropped out, a CDI that centered late
• Gyro health: an attitude indicator slow to erect or that precessed in the turns, a heading indicator that needed frequent resets
• Autopilot disconnects or mode weirdness
• Electrical and vacuum/pressure trends you noticed on the gauges
• Ordinary servicing: fuel, oil, oxygen, tires and brakes

Capture it while it's fresh — a squawk you can't remember by the time you reach the FBO desk never gets fixed (IR.VIII.A.S1).

Document it in whatever discrepancy system the operator uses — squawk sheet, maintenance log, a call to the shop — with enough detail to be useful to a technician: what happened, when, in what conditions, which frequency and approach. The owner or operator must have defects repaired between required inspections as prescribed by Part 43, but that machinery only starts when the defect is written down (91.405(a)). The unwritten half: an undocumented squawk becomes the next pilot's in-flight surprise — and in this airplane the next pilot may be shooting an ILS to minimums.

The owner or operator, who must:

• Have discrepancies repaired between required inspections as prescribed in Part 43 (91.405(a))
• Ensure maintenance personnel make the return-to-service entries in the maintenance records (91.405(b))
• Have any item deferred inoperative under 91.213(d)(2) repaired, replaced, removed, or inspected at the next required inspection (91.405(c))
• Ensure a placard is installed when listed discrepancies include inoperative instruments or equipment (91.405(d))

You still own the pilot half: deciding whether the airplane is airworthy for the next flight.

Yes, if every step of the deferral test passes (91.213(d)):

1. Eligible aircraft — a rotorcraft, non-turbine airplane, glider, lighter-than-air aircraft, powered parachute, or weight-shift-control aircraft with no Master MEL, or a small rotorcraft, non-turbine small airplane, glider, or lighter-than-air aircraft that has one
2. The item is not required by the aircraft's VFR-day type certification, its equipment list or Kinds of Operations Equipment List, 91.205 or any other rule for the specific kind of flight operation, or an airworthiness directive
3. The item is removed (cockpit control placarded, maintenance recorded under 43.9) or deactivated and placarded "Inoperative" (deactivation involving maintenance is done and recorded per Part 43)
4. A pilot or maintenance person certificated and appropriately rated determines it's no hazard to the aircraft

The IFR wrinkle in that "specific kind of flight operation" clause: equipment 91.205(d) requires for IFR can't be deferred for an IFR flight. The full airworthiness decision ladder is covered under Task II.C.

A Minimum Equipment List is an FAA-approved, aircraft-specific list providing for operation with certain items inoperative. Operating under one requires a letter of authorization from the Flight Standards office carried in the aircraft — the MEL and letter together constitute a supplemental type certificate. The aircraft records available to the pilot must include an entry describing the inoperable items, and you must observe every condition and limitation in the MEL and letter (91.213(a)).

Most light trainers have no MEL — they run on the 91.213(d) deferral method instead. Be ready to say that plainly.

A special flight permit — an aircraft with inoperable instruments or equipment may be operated under one, issued in accordance with 21.197 and 21.199, to get it to where repairs can be made (91.213(e)).

Three piles:

• Work records — for each maintenance, alteration, and inspection: a description of the work, the date completed, and the signature and certificate number of the person approving return to service. Kept 1 year or until the work is repeated or superseded.
• Permanent status records — total time in service, current status of life-limited parts, time since overhaul of time-limited items, current inspection status, AD compliance status (method and date), and copies of the 43.9(d) major-alteration forms. Retained and transferred with the aircraft when it's sold.
• Inspection defect lists — a list of defects furnished under 43.11, kept until the defects are repaired and the aircraft is approved for return to service (91.417(b)(3)).

All of it must be made available to the FAA or NTSB on request (91.417(c)). Your postflight squawk is the first link in that paper trail.

The VOR operational check. To use the VOR under IFR it must have been checked within the preceding 30 days, and whoever does the check enters the date, place, bearing error, and signature in the aircraft log or other record (91.171(d)). It's the one recurring IFR record that's pilot-made rather than mechanic-made — check methods and error limits are covered under Task II.C.

Because the failures that matter most under IFR are invisible on the ramp. A gyro that precesses under load, a glideslope receiver that drops out intermittently, an altimeter that sticks — all of them pass a ground check and then resurface in IMC, where partial panel is a genuine emergency rather than a hood exercise. The only thing standing between that airplane and the next low-IMC departure is your written squawk. Same logic for servicing trends: a slowly sagging vacuum reading or an ammeter drifting low is a report, not a shrug.