Somatogravic: All Was Well for a Pilot, and Then It Suddenly Wasn’t

Illusion can occur during rapid acceleration and deceleration in flight.

Peter Garrison

Tuesday, May 27, 2025 at 07:49 AM ET

Verified

Edited By:

Travis Tingle

Somatogravic illusion (SGI) is a stealthy killer. [Shutterstock]

Key Takeaways:

A Citation 501 crashed in May 2021, killing seven people, shortly after takeoff into overcast conditions due to the pilot experiencing severe spatial disorientation, specifically the somatogravic illusion.
The pilot exhibited erratic flight behavior, including unexpected descents and climbs, and struggled to maintain assigned altitude and heading despite ATC instructions.
Although type-rated and experienced, the pilot had limited actual instrument time and a history of difficulties with situational awareness and the Citation's autopilot, preferring to hand-fly.
The accident underscores that spatial disorientation can affect even seemingly capable pilots in benign instrument meteorological conditions if they fail to consistently rely on instruments over physical sensations.

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In May 2021, seven people died when a Citation 501, N66BK, crashed into Percy Priest Lake near Nashville, Tennessee, shortly after taking off.

It was a little before 11 a.m. There was an overcast at 1,300 agl (1,850 msl), but no precipitation and good visibility below the clouds. The pilot had topped off the plane for the two-hour flight from Smyrna Airport (KMQY) to Palm Beach International Airport (KPBI) in Florida. After taxiing to Runway 32, he was instructed to turn to a heading of 090 after takeoff and maintain 3,000. His IFR clearance, which he had received previously, said to expect a climb to FL 330 10 minutes after departure.