What happened
During a test flight following a recent alternator replacement, a Cessna 150 performed a series of low passes over various runways. While executing a turn from the downwind leg of runway 12 toward runway 30, witnesses reported hearing a loud "pop." During this final turn, the aircraft entered a stall and descended into the ground. The aircraft struck the earth 94 metres from the runway threshold in a nose-down, upright position before bouncing, nosed-over, and coming to rest inverted. The pilot sustained fatal injuries in the crash.
The investigation
Investigators examined the wreckage and found the aircraft's flight controls were fully functional and continuous. While the engine was found with a non-standard pipe fitting in the carburettor due to a missing finger screen, this was not determined to be a factor in the accident. The engine was capable of producing full power, and the airspeed indicator recorded 50 knots at the moment of impact. Notably, the wing flaps were in the retracted position, which differed from the pilot's typical landing configuration.
Post-accident toxicological analysis of the pilot revealed the presence of ethyl alcohol, fluoxetrine (Prozac), and trace amounts of an antihistamine. While the alcohol level was below the legal driving limit, the pilot had not disclosed his use of prescribed anti-depressants to medical examiners during his last medical assessment.
Findings
- The aircraft experienced a stall during a steep-banked turn while transitioning from the downwind leg to final approach.
- The pilot was unable to recover from the stalled state before the aircraft impacted the ground.
- The steep bank angles, estimated between 60 and 90 degrees, significantly increased the aircraft's stall speed beyond its actual airspeed at impact.
- The pilot had not reported his use of prescription medication to aviation medical authorities.