What happened
On 21 November 1998, a Slingsby T61F Venture T MK2 motor glider, registration G-BUGV, was conducting a private training flight at Enstone Airport. The commander was flying with a student pilot to assess their ability to handle crosswind conditions. Due to the humid, cool weather, which was prone to causing carburettor icing, the crew was being particularly diligent with the use of carburettor heat.
During the third circuit, shortly after takeoff, the engine suffered an abrupt and total loss of power at an altitude of approximately 300 feet. While the handling pilot attempted to restore power by manipulating the throttle, the commander took control to execute an emergency landing. During the turn toward the reciprocal runway, the aircraft lost airspeed and entered a nose-down, wing-low attitude. The crew managed to level the wings and flare for a touchdown on a grass area. However, the aircraft bounced over a disused taxiway and struck soft ground on a second touchdown, causing the propeller to pitch forward and sustain damage. There were no injuries to the two occupants.
The investigation
Investigators examined the engine performance and the environmental conditions at the time of the accident. Following the incident, the pilot conducted further test flights in similar weather. These tests revealed that while the engine responded normally to carburettor heat selection, the engine speed would eventually rise above normal levels when the heat was switched back to cold.
Additionally, the investigation noted that the engine had experienced two subsequent unexplained stoppages while on the ground. While the aircraft's single magneto was suspected, subsequent examination of the component failed to reveal any specific defects.