What happened
On January 25, 1997, at approximately 16:20 local time, a SOCATA Rallye 150 SV, registration F-GBSK, experienced an engine failure while performing a solo flight in the circuit at Châteaubriand aerodrome. The aircraft was flying in a downwind pattern at an altitude of 800 feet when the engine ceased operation.
In response to the loss of power, the trainee pilot attempted an emergency landing in a nearby field. During the approach, the aircraft struck two power lines that were not visible to the pilot. The impact with the cables caused the windshield and the left wing to strike the wires, resulting in the cables being severed and causing structural damage to the wing tip and the leading edge. Following the impact, the aircraft lost speed, pivoted, and made a hard landing, with the tail section striking the ground.
The investigation
The investigation focused on determining the cause of the engine failure and the circumstances of the impact with the power lines. An examination of the wreckage conducted the following day revealed that the engine was capable of starting without any mechanical issues. The investigation established that the engine failure occurred specifically during a change in cockpit configuration.
Findings
The investigation concluded that the engine failure was caused by control confusion within the cockpit. It is highly probable that the trainee pilot mistakenly manipulated the mixture and carburetor heat controls, which effectively choked the engine and caused it to stop.