Soft-Field Takeoff and Climb (ASEL)

Soft field: get the airplane airborne as quickly as possible to eliminate the drag caused by tall grass, soft sand, mud, and snow. Rough field: get off the ground as soon as possible to avoid damaging the landing gear (AFH ch. 6).

The mechanism is one idea: transfer the support of the airplane's weight as rapidly as possible from the wheels to the wings by establishing and holding a relatively high AOA as early as possible (AI.VII.C.K6; AFH ch. 6). Every technique element follows from that sentence.

1. "Flaps set per the POH — extra lift, weight off the wheels sooner."
2. "We do not stop. Stopping on mud or snow can bog us down — keep rolling onto the runway."
3. "Back pressure coming in now, power up smoothly as we line up."
4. "Nose light — you can feel the nose gear unload."
5. "Hold this attitude. The airplane will fly itself off."
6. "Airborne — now lower the nose slightly, stay in ground effect, accelerate."
7. "VX/VY as appropriate — now we climb."
8. "Positive rate and clear of obstacles — flaps up in increments."

The ACS wants this exact shape:

1. Taxi into position and align on the centerline without stopping, while advancing the throttle smoothly to takeoff power (AI.VII.C.S6)
2. A pitch attitude that transfers weight from wheels to wings as rapidly as possible (S8)
3. Lift off at the lowest possible airspeed and remain in ground effect while accelerating to VX or VY (S9)

• Establish a pitch attitude for VX or VY as appropriate and maintain the selected airspeed ±5 knots during the climb
• Maintain VX or VY, as appropriate, ±5 knots to a safe maneuvering altitude
• Configure after a positive rate of climb has been verified or per the manufacturer
• Maintain directional control and proper wind-drift correction throughout, complete checklists, verify the correct runway, make radio calls, comply with noise abatement
• Analyze and correct common errors (S15)

Ten (AFH ch. 6):

1. Failure to review AFM/POH and performance charts prior to takeoff
2. Failure to adequately clear the area
3. Insufficient back-elevator pressure during the initial roll, resulting in inadequate AOA
4. Failure to cross-check engine instruments after applying power
5. Poor directional control
6. Climbing too high after lift-off and not leveling off low enough to maintain ground effect
7. Abrupt and/or excessive elevator control while attempting to level off and accelerate
8. Allowing the airplane to "mush" or settle, resulting in an inadvertent touchdown after lift-off
9. Attempting to climb out of ground effect before attaining sufficient climb speed
10. Failure to anticipate an increase in pitch attitude as the airplane climbs out of ground effect

Errors 6 through 9 are one continuous problem — the transition from lift-off to accelerating in ground effect — and that is where nearly every soft-field bust occurs.

Say the correction as a picture, not a number: "Nose down a hair — hold it right there, wheels a foot off the grass. Let the speed build."

What happens if they hold it: the airplane has a tendency to settle back onto the surface even with full power applied while transitioning out of ground effect, so it is essential that the airplane remain in ground effect until at least VX is reached (AFH ch. 6). Out of ground effect below the recommended climb speed, initial climb performance is much less than at VY or even VX, and under high density altitude, high temperature, or maximum gross weight the airplane may be unable to climb out of ground effect at all and may not clear obstructions.

The recovery once high and slow is not "pull harder." Since climb is at maximum power already, reducing drag is the only option — and reducing drag means reducing pitch, which means losing altitude. Brief that consequence on the ground; it is a terrible thing to discover at 20 feet.

Because the airplane stays in contact with the drag it was supposed to escape. Taking off from a soft surface or through long, wet grass reduces the airplane's ability to accelerate and may prevent it from reaching adequate takeoff speed if normal takeoff technique is used (AFH ch. 6). The nose gear also stays loaded on exactly the surface most likely to catch it.

The verbal fix is tactile: "More back pressure — keep coming back until the nose gets light, then stop and hold." Then debrief the cause, which is almost always that the student is looking at the nose instead of holding a picture of the horizon.

The technique does not change; the margins do.

• Crosswind — you still apply full aileron into the wind at the start of the roll and hold enough to keep the upwind wing from rising (AFH ch. 6). The conflict is real: you are lifting off at the lowest possible airspeed with a high AOA, precisely when drift authority is weakest, so a crosswind that is unremarkable for a normal takeoff can make a soft-field takeoff a poor idea.
• Windshear and tailwind — a tailwind lengthens the roll on a surface that is already stealing acceleration; confirm the POH approves a tailwind takeoff and that performance and length exist (AFH ch. 6).
• Wake turbulence — rotating before the point where a preceding heavy airplane rotated is the standard mitigation (AFH ch. 6), and a soft-field takeoff naturally lifts off early, which helps.
• Surface/condition — this is the input that chose the technique in the first place; if wet snow or slush is on the surface, do not retract the gear immediately so it can air-dry.

Before you roll, out loud:

• A go/no-go point on the field — identify a point at which the airplane should be airborne; if that point is reached and the airplane is not airborne, discontinue the takeoff immediately (AFH ch. 6). On a soft field this point comes with less deceleration margin, because a soft surface also shortens the stop.
• A ground-effect floor — if the airplane leaves ground effect below VX with obstacles ahead, you are taking the controls, lowering the nose, and accepting the field.
• Engine failure in the climb — lower the nose immediately to prevent a stall, coordinate, and glide preferably straight ahead; no turn back unless specifically trained with sufficient altitude (AFH ch. 6).

State the trigger and the phrase together in the brief: "If I say 'I have the flight controls,' let go and put your hands on your lap." (AIH ch. 9)

Because they optimize opposite things, and mixing them is dangerous — the correct takeoff procedure for soft fields is quite different from the procedure used for short fields with firm, smooth surfaces (AFH ch. 6).

Soft field wants the weight off the wheels now — high AOA early, lift off at the lowest possible airspeed, accelerate in ground effect. Distance is not the objective.

Short field wants minimum drag and maximum acceleration — the airplane rolls with its full weight on the main wheels, in a low-drag attitude, and rotates at VX. Holding it on the ground unnecessarily with forward pressure puts excessive pressure on the nose-wheel and may result in wheelbarrowing (AFH ch. 6), which is why short-field technique on a soft field is destructive.

A soft and short field takes the soft-field technique for lift-off followed by a VX climb until obstacles are cleared, then VY (AFH ch. 6).

Because it reallocates the load. When the airplane is held at a nose-high attitude throughout the takeoff run, the wings increasingly relieve the wheels of the airplane's weight as speed increases and lift develops, thereby minimizing the drag caused by surface irregularities or adhesion (AFH ch. 6). Wheel drag on a soft surface is roughly proportional to the load the wheels carry; move that load to the wings and the drag goes away with it.

The trade is induced drag — a high AOA is an expensive way to make lift — which is exactly why the technique is wrong on a firm short field, where wheel drag is negligible and induced drag would dominate.

Consequence to teach: if the attitude is accurately maintained, the airplane virtually flies itself off the ground, becoming airborne at an airspeed slower than a safe climb speed because of ground effect. The student should not be "rotating" — they should be waiting.

Because it is what makes an early lift-off survivable and what makes a premature climb fatal. Ground effect is a reduction in induced drag caused by reduced upwash, downwash, and wingtip vortices near the surface, detectable up to about one wingspan; the reduction is about 25% at ¼ span height and about 50% at 1/10 span (AFH ch. 6). It is not a cushion of air — that "apparent increase in airplane performance is borrowed performance that is repaid when the airplane climbs out" (AFH ch. 9).

The four things that happen on the way out, all felt within two seconds (AFH ch. 6):

• An increase in AOA required to maintain lift coefficient
• An increase in induced drag and thrust required
• A pitch-up tendency requiring less elevator travel because of increased downwash on the tail
• A reduction in static source pressure with a corresponding increase in indicated airspeed

That last item is why the ASI reads low in ground effect and appears to jump as you climb out — teach it so the student does not chase it.

VX: the speed at which the airplane achieves the greatest gain in altitude for a given distance over the ground. VY: the greatest gain in altitude per unit of time — usually slightly more than VX (AFH ch. 6).

The "why" a student will ask: VX is where excess thrust is greatest; VY is where excess power is greatest. Distance-limited obstacle problems are thrust problems; time-limited climb problems are power problems.

The number that makes it matter operationally: in some airplanes a deviation of 5 knots from the recommended speed may result in a significant reduction in climb performance — which is precisely why the standard is ±5 knots and not a suggestion (AFH ch. 6).

For the soft-field Task you climb at VX or VY as appropriate (AI.VII.C.S10) — VX only if an obstacle requires it, then transition to VY.

More of everything, for longer. The soft-field takeoff spends its whole roll and lift-off at high power, high AOA, and low airspeed — the exact corner where P-factor (higher AOA on the descending blade) and spiraling slipstream (corkscrew flow onto the left side of the fin) are strongest, while torque reaction is loading the left main into the soft surface you are trying to escape.

Two teaching consequences: poor directional control is a listed common error for this Task, and it is not a coincidence — the rudder demand is higher and lasts longer than in a normal takeoff. The rudder requirement decreases as you accelerate in ground effect, so a fixed foot position that was right at lift-off produces a sideslip ten seconds later — costing you the acceleration you are trying to gain.