Spatial Disorientation Cited in Helicopter Accident
Spatial disorientation is the likely reason the pilot of a privately owned Robinson R44 helicopter lost control of the aircraft and crashed near southern Quebec’s Saint-Ferdinand Aerodrome in August 2011, according to the accident report issued by the Transportation Safety Board of Canada (TSB). The private pilot and the three passengers aboard, all members of the pilot’s family, were killed in the nighttime accident.
The helicopter crashed just after takeoff from an unlit field for a return trip to the pilot’s residence in Saint Nicholas approximately 37 miles away. Although the pilot was current according to the letter of the Canadian Air Regulations, all of the six hours of night flight time he’d logged in the previous six months took place at locations that were well lit. The area in which the accident happened provided little or nothing in the way of ground-based references. Canadian Air Regulations do not allow VFR departures at night when an aerodrome is unlit.
The spatial disorientation determination evolved from an understanding that humans essentially gather 80 percent of their ability to maintain their equilibrium from what they see.
In this accident, no one visually witnessed the takeoff or the crash; witnesses reported hearing the sound of the impact at around 9 p.m. local time.
Weather in the area included visibility of eight to nine miles with scattered to broken cloud, making it unclear whether the pilot could have seen the moon or stars. The report alluded to other possible pressures on the pilot that night, including the short distance of the return flight, the appearance of good visual conditions and an approaching weather system that would have made flight nearly impossible and necessitated delaying the flight until the next day.