What happened
On 21 July 2012, a Thruster TST Mk1, registration G-MTKA, was conducting a training flight from Otherton Airfield in Staffordshire. Shortly after takeoff, while the aircraft was at an altitude of approximately 100 ft, the engine lost power. To avoid encountering power lines and a nearby hedge, the pilot performed a 90-degree turn to the right toward a crop field.
During the subsequent landing, the right wing of the aircraft made contact with the crops. This contact triggered a ground loop, which caused significant damage to the aircraft's wings, the nose fairing, and the main fuselage tube. There were no injuries to the two crew members on board.
The investigation
The investigation examined the engine's condition following the incident. Upon inspection, the engine was found to have been stripped, revealing scoring marks on the exhaust side of both pistons. These marks were consistent with engine overheating and seizure. The pilot indicated that the failure was caused by misadjusted carburetor jet needles in both carburetors, which had resulted in the engine operating with a lean mixture.
Findings
- The engine failure was caused by engine overheating and seizure.
- The overheating was a result of the engine running with a lean mixture due to misadjusted carburetor jet needles.
- The ground loop and subsequent structural damage were a consequence of the right wing striking the crop during the landing maneuver.