Runway Visual Perspective
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Correctly judging the required angle of approach to a landing runway when using only direct visual reference, with no external slope indication such as VASI or PAPI and with no ILS GS display or non-precision approach plate to refer to, can be challenging when not carried out regularly. The difficulty may be greater at night because visual cues may be restricted to lit objects and runway lighting systems.
The Runway Visual Perspective may give rise to a visual illusion that may result in landing short of the runway, hard landing or runway overrun, but may also cause spatial disorientation and loss of control.
The errors related to wrong angle of approach based on visual cues occur more often during the hours of darkness. Contributory factors are specifics of the terrain, airport environment (e.g. absence of lights creating 'black hole effect') and weather conditions. Some common scenarios include:
- Perception that the aircraft is too high - The pilot of an aircraft approaching a very long runway gains the impression that the aircraft is high on the approach and descends dangerously close to the ground;
- Runway slope and mis-perception of the aircraft position based on visual reference The pilot of an aircraft approaching a runway with a pronounced up-slope gains the impression that the aircraft is high on the approach and descends dangerously close to the ground;
- Mis-identification of the runway: The pilot sees a row of street lights and mistakenly lines up on them instead of the runway (see also Wrong Runway Use);
Visual Illusions Awareness
The Airbus Flight Operations Briefing Note (FOBN) - Visual Illusions Awareness provides a more detailed description of the problems, aided by clear diagrams, and providing more detail on the defences to adopt.
Other relevant sources of information from the Flight Safety Foundation ALAR Toolkit are listed below under Further Reading.
Accidents & Incidents
- B737, vicinity Branson MO USA, 2014 (On 12 January 2014, a Boeing 737-700 making a night visual approach to Branson advised 'field in sight' approximately 20 miles out and was transferred to TWR and given landing clearance at approximately 6,000 feet. However, the crew had misidentified the airport and subsequently landed on a similarly-orientated runway at a different airport. The Investigation found that required flight crew procedures for such an approach had not been followed and also that applicable ATC procedures for approval of visual approaches by IFR flights were conducive to pilot error in the event that airports were located in close proximity.)
- B763, Atlanta GA, USA 2009 (On 19 October 2009, a Boeing 767-300 being operated by Delta Airlines on a scheduled passenger flight from Rio de Janeiro to Atlanta inadvertently made a landing at destination in night VMC on parallel taxiway ‘M’ instead of the intended and ATC-cleared landing runway 27R. None of the 194 occupants were injured and there was no damage to the aircraft or conflict with other traffic or vehicles. The third rostered crew member had become incapacitated en route with the consequence that neither of the other pilots had been able to take any in flight rest.)
- B752, Newark NJ USA, 2006 (On 28 October 2006, a Boeing 757-200 being flown by two experienced pilots but both with low hours on type was cleared to make a circling approach onto runway 29 at Newark in night VMC but lined up and landed without event on the parallel taxiway. They then did not report their error and ATC did not notice it after Airport Authority personnel who had observed it advised ATC accordingly, the pilots admitted their error.)
- AS65, vicinity North Morecambe Platform Irish Sea UK, 2006 (On 27 December 2006, an AS365 Dauphin 2, operated by CHC Scotia, crashed into the sea adjacent to a gas platform in Morecambe Bay, UK, at night, following loss of control.)
- B732, London Gatwick UK, 1993 (On 20 October 1993, a Boeing 737-200 being operated by Air Malta on a scheduled passenger flight from Malta to London Gatwick landed at destination on the taxiway parallel to the runway for which landing clearance had been given in good visibility at night after a Surveillance Radar Approach (SRA) terminating at 2 miles from touchdown had been conducted in VMC. There was no damage to the aircraft or injury to the occupants and the aircraft taxied to the allocated gate after the landing.)
- Flying a Visual Approach
- Night Visual Approaches
- Visual Illusions
- Runway Excursion
- Stabilised Approach
- OGHFA Spatial Disorientation Situational Example
Flight Safety Foundation