Night Operations

Cones are concentrated in the center of the retina: sharp detail and color, but they need light. Rods surround them in the periphery, far more light-sensitive but no color and poor detail. At night the fovea becomes a central blind spot, so I use off-center viewing: look about 5–10° to the side of an object and scan slowly rather than staring (PHAK ch 17, AIM 8-1-6).

Rods take roughly 30 minutes to fully adapt to darkness (cones adapt in about 10). One blast of bright white light resets the clock, so I use low-intensity cockpit lighting, avoid bright lights before and during flight, and close one eye if exposure is unavoidable. Red light preserves night vision but washes out red chart markings; oxygen helps too, since night vision degrades noticeably above about 5,000 ft cabin altitude (AIM 8-1-6, AFH ch 11).

Everything for day VFR plus the night items: approved position lights, an approved anticollision light system, a landing light if operated for hire, an adequate source of electrical energy, and spare fuses (one spare set or three of each kind) if the airplane uses fuses. Position lights must be on from sunset to sunrise (91.209).

To carry passengers between 1 hour after sunset and 1 hour before sunrise, I need 3 takeoffs and landings to a full stop in that same window, in the same category and class, within the preceding 90 days (61.57(b)).

Three "nights" to keep straight:

• Position lights: sunset to sunrise (91.209).
• Logging night time: end of evening civil twilight to beginning of morning civil twilight (1.1, 61.51).
• Passenger currency: the 1-hour-after / 1-hour-before window.

• Rotating beacon: white/green for a lighted civilian land airport (beacon on during the day suggests IFR weather in Class B/C/D/E surface areas).
• Runway: edge lights white (yellow on the last 2,000 ft of an instrument runway), green threshold / red runway end, REIL for identification, VASI/PAPI for glidepath.
• Taxiways: blue edge lights, green centerline.
• Pilot-controlled lighting: key the mike 7 times for high intensity, then 5 or 3 to adjust; I always key 7 first (AIM 2-1).

Red is on its left wingtip, green on its right, white on the tail.

• Red and green, no white: coming at me, so I alter course right.
• White only: I'm overtaking it or it's moving away.
• Green only: crossing left to right.
• Red only: crossing right to left, and likely has the right-of-way (91.113, AIM 4-3).

• Black-hole approach: no terrain lighting on final, so the tendency is to fly a dangerously low approach; use the VASI/PAPI.
• False horizon: sloping cloud decks or ground lights mistaken for the horizon.
• Autokinesis: a stared-at static light appears to move, so keep the scan moving.
• Featureless terrain illusion.
• Flicker vertigo: from strobes in cloud or the prop in low sun/landing light.

Bright runway lighting can make the runway seem closer than it is (PHAK ch 17, AIM 8-1-6).

Same flow (best glide, checklist, declare, squawk 7700), but field selection is the hard part. Head for dark areas near lighted roads and towns (dark usually means open land), use the landing light on final to see the surface, and keep the airplane under control all the way through touchdown at the slowest safe speed. Planning night routes over lighted corridors and within glide of airports is the risk-management answer (AFH ch 11).