Black-Hole Approach at a Coastal Runway
At 23:40 local time, a twin-turboprop is on a visual approach to Runway 27 at a coastal airport. The runway has no VASI or PAPI on this side, the approach lighting ends 60 m before the threshold, and the terrain beyond the runway rises gradually. The night is moonless and overcast; there are no lights between the aircraft and the runway. The pilot, who has flown this route many times, reports the aircraft 'looks high' and reduces power. The first officer, on his first night approach to this runway, thinks they are low but does not challenge. Radio altimeter calls are available. At 300 ft AGL the first officer sees the runway edge lights appear to rise rapidly. The aircraft is at 1.4 nm final, speed 130 kt, sink rate 900 ft/min.
1. Identify the illusion and explain how the visual cues in this scenario create a false glidepath perception.
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This is a classic black-hole approach. The absence of ground lights between the aircraft and the runway removes motion parallax, texture and horizon cues. The pilot's visual system then relies on the runway outline, its brightness and the approach lights. A narrow runway makes the aircraft appear higher than it is; an upsloping runway or rising terrain beyond the threshold can have the same effect. The approach lighting ending before the threshold adds to the impression that the aircraft is too high.
The pilot responds by reducing power, which increases sink rate and lowers the flightpath. The result is a low approach, not a high one. The first officer's perception is probably closer to reality, but he does not challenge because of the captain's experience and the dark, featureless view. The rising runway edge lights at 300 ft are a strong warning of excessive sink and imminent ground contact. Vision is misleading here; the radio altimeter and instrument cross-check are the reliable references.
2. Why is the first officer's perception important, and what instruments or cues should the crew use to resolve the conflict?
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The first officer's perception matters because two independent visual estimates conflict. In a black-hole approach, the pilot flying may be confidently wrong; a second crew member who thinks the aircraft is low is a safety barrier. His failure to speak is a communication and coordination failure, reinforced by the authority gradient and his unfamiliarity with the runway.
The crew should resolve the conflict with independent references: radio altimeter against distance-to-go, barometric altimeter against the published approach profile, vertical speed, airspeed, glidepath or ILS indication if available, and the runway aiming point. At 1.4 nm and 300 ft AGL with 900 ft/min sink, the aircraft is not on a normal 3° path; the sink rate is excessive for the final segment. The absence of VASI does not remove the need for a stabilised approach. The first officer should state the specific deviation-height, speed, sink rate-rather than a vague 'we look low', and should call for a go-around if the deviation continues.
3. State the correct action at 300 ft AGL and the follow-up actions.
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At 300 ft AGL, the correct action is an immediate go-around. The aircraft is unstable: excessive sink rate, a low visual picture and a first officer who perceives a dangerous deviation. The pilot flying should apply go-around thrust, pitch to the go-around attitude, call for flaps, confirm positive rate, retract gear as appropriate and follow the published missed approach. There is no attempt to salvage the landing.
After the go-around, the crew should debrief the illusion and file an occurrence or ASAP report. The captain should acknowledge the first officer's call and explain the black-hole effect. For future approaches, the crew should brief the lack of visual cues, use the radio altimeter and any available glidepath, set a hard stabilised-approach gate and agree that either pilot can call go-around. Training should include night visual illusions and assertiveness. The operator should also review whether the runway needs VASI/PAPI or additional approach lighting.