What happened
On 10 February 2024, an Aerosport Scamp, registration G-BOOW, was performing a private flight near RAF Mona, Anglesey. The aircraft, which had recently undergone a major restoration, was being flown by a pilot performing a series of right-hand circuits. Following a normal pre-flight inspection, the aircraft departed from Runway 04.
Shortly after takeoff, at an altitude of approximately 400 ft, the engine experienced a significant decrease in RPM accompanied by rough running. The pilot lowered the nose to maintain airspeed, causing the aircraft to descend to 300 ft. During this period, the engine unexpectedly returned to full power. Attempting to fly a tight circuit to maintain options for landing, the pilot reached 600 ft on the downwind leg when the engine power dropped to idle with significant roughness.
Unable to reach the airfield, the pilot selected a field for a forced landing. During the maneuver, the aircraft experienced a stall with a right wing drop. As the pilot pitched the nose down to recover, the engine stopped completely. To avoid a residential area, the pilot directed the aircraft into a line of trees within an open garden area. The aircraft was destroyed upon impact, and the pilot sustained serious injuries, including a fractured wrist and a minor head injury.
The investigation
The investigation examined the engine and the circumstances of the flight. Post-accident inspections of the engine showed that all four cylinders had good compression and the crankshaft rotated freely. The oil level was found to be normal, and there were no visible signs of electrical arting within the ignition system.
The pilot noted that the Aerosport Scamp is a high-drag, low-inertia aircraft with a narrow margin between climb speed and stall speed. The pilot also experienced a 'startle effect' following the initial power loss, which contributed to a decay in airspeed. The investigation could not determine the specific cause of the engine's power fluctuations or eventual failure.