Optical Illusion Cited in Crash

The Transportation Safety Board says an optical illusion likely contributed to the crash of a Beaver on floats in central B.C, in October of 2016. The TSB report also noted the plane was 300 kg. overweight when it stalled and crashed near Laidman Lake. The pilot was killed and two of four passengers seriously hurt. The report says the pilot likely misjudged his altitude because the lack of visual cues while flying over snow-covered terrain in overcast conditions.

“The lack of features to provide scale in the snow-covered terrain, together with the minimal contrast among the dense trees given the diffuse light conditions, likely disguised the upsloping terrain and the actual horizon,” the report says. “As the slope steepened, the perceived horizon would have moved upward in the windscreen, and the pilot may have pitched the aircraft up to maintain a constant angle between the pilot’s reference point on the aircraft and the rising terrain.” The TSB also said a stall horn, which the Beaver lacks, might have helped.