What happened
While maintaining level flight, a Cessna 150 entered a left-hand turn that transitioned into a spiral dive, ultimately resulting in a high-speed, steep collision with the ground. The impact was non-survivable, resulting in 1 fatality. The aircraft's flight path data showed that once the descent began, there were no recorded corrective control inputs from the pilot to recover the aircraft from the maneuver.
The investigation
Investigators examined several potential causes, including mechanical failure, control jams, and spatial disorientation. Analysis of the engine and propeller confirmed the engine was operational at the time of the accident. Because the surrounding area consisted of flat, unobstructed paddocks suitable for an emergency landing, the lack of any attempt to divert or any distress calls on the common traffic advisory frequency suggested that no engine or mechanical emergency occurred.
Regarding flight controls, the aircraft had recently been fitted with new control cables, and the pilot had maintained stable, level flight for over 30 minutes prior to the event, indicating the controls were functioning correctly. Furthermore, the clear weather conditions and high visibility made spatial disorientation unlikely. The investigation noted that the pilot's lack of corrective action during the spiral dive was highly unusual for a pilot of their experience level.
Findings
- The pilot likely suffered an incapacitating medical event while in cruise flight.
- The pilot had been suffering from an acute gastrointestinal illness in the days leading up to the flight and was likely still symptomatic during the flight.
- The medical event led to a deviation from the flight path, a left-hand spiral dive, and the subsequent impact with the terrain.