Accident Report
http://tsb.gc.ca/eng/rapports-report...6/a01c0236.pdf
The loss of visual references as the aircraft accelerated along the runway and past the lights of the community were ideal for the onset of somatogravic illusion in the pilot flying. Even 7 seconds prior to impact, the captain believed that he was climbing to 1000 feet above ground level. The captain’s performance was consistent with his being unable to distinguish the imposed acceleration as the aircraft speed increased from that of gravity and, although he probably thought the aircraft was climbing, it was not.
The first officer may also have been influenced by the somatogravic illusion. During the 30 seconds of the missed approach, his tasks were to react to the captain’s commands and to monitor the instruments. Apparently the first officer did not observe anything remarkable or he would have alerted the captain that the aircraft was not climbing.
It is possible that he was distracted by the sudden sound of the NDB identifiers just after the missed approach was initiated. The NDB receiver was turned off just prior to impact, and since the control head is on the first officer’s side of the cockpit, it was likely he who turned the NDB off. Given the short duration of the overshoot and the tasks that the first officer was performing, it is probable that he had a false perception that the aircraft was climbing.
Even though the conditions were present for the crew to be affected by somatogravic illusions, these illusions could have been overcome by at least one of the crew. During the visual approach, the pilots were able to fly with visual reference to the surface. However, pilots are required to transition to instruments when entering, or about to enter, weather or environmental conditions where visual flight conditions do not prevail, as was the case when
the overshoot was initiated. Had this transition been made, the fact that the aircraft was not climbing would have been evident.
The company SOPs for the missed approach was less stringent than those for the company’s training school. There was no stated requirement to use instruments during a missed approach nor a requirement to identify two positive rates of climb. The use of these two techniques would be a stronger defence against the possibility of somatogravic illusion and loss of situational awareness.
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High acceleration during take-off and initial climb can cause an illusion of increasing pitch. Somatogravic illusion (aka the "pitch-up illusion") is an erroneous sensation of pitch (rotation in the vertical plane) caused by linear acceleration. Under normal conditions this sensation can be recognized and corrected by visual means; however, when a take-off (or go-round in particular) is being made on a very dark night, and toward an area that provides few visual references, this illusion will remain a powerful influence. A pilot's normal response to this pitch-up illusion is to apply forward pressure to the control column, and to reduce the aircraft's angle of climb. As the pilot unloads, so the acceleration forwards is reinforced by the negative g and so the illusion is thus progressively (and rapidly) enhanced.
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Air Afriqiyah A330
Sudden loss of forward vision due to sunrise glare, accompanied by a fair expectation of regaining it momentarily, would deter a pilot from getting back on the clocks, particularly if he knew that he was quite close to the ground.
Sudden unexpected loss of forward vision in conditions of sunrise and sunset landings is not at all uncommon. Fly long enough and it will happen to you. If accompanied by an attempt to go round, then the light-weight aircraft's rapid acceleration during mandatory TOGA can suddenly become a player. The fact that both pilots can experience the phenomenon simultaneously (see above and GF072 Report) is also a factor. Consider also that if a non-handling captain is looking outside for visual cues when he experiences this overpowering illusion, he may well intervene and take drastic action - such as stuffing the nose down. At ow altitude an unrecoverable attitude is always likely to result.
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Dark Night Takeoffs
http://www.pprune.org/tech-log/9199-...-illusion.html
Untitled Document
Transportation Safety Board of Canada - AVIATION REPORTS - 1996 - A96C0002
Untitled Document
http://www.pprune.org/rumours-news/4...nce-gf072.html
Approach and landing illusions
Untitled Document