What happened
On 10 May 2008, a Mainair Rapier, registration G-MZGL, was performing a private flight from Clotton. This flight marked the aircraft's return to service following a period of several months in storage. After completing all necessary pre-flight and power checks, the pilot departed from Runway 10 under favorable weather conditions, characterized by light and variable winds.
Shortly after the departure, the aircraft's rate of climb began to diminish. Despite the pilot increasing pressure on the throttle lever, the engine failed to provide the necessary performance to maintain altitude. The aircraft reached a maximum height of approximately 30 to 50 feet before entering a descent, eventually striking trees located roughly 150 metres beyond the runway end. The pilot, who was wearing a helmet and a lap strap, sustained minor injuries, though the aircraft suffered major damage to the trike and damage to the wing.
The investigation
Investigators examined the engine following the accident. The inspection of the Rotax 503-2V piston engine identified a greenish-grey deposit within the engine. This substance was found to be partially obstructing one of the main jets in the carburettor. The nature of the deposit suggested it was micro-bacterial in origin, likely having developed during the aircraft's extended period of storage.