Incident
On 3 September 2000, at approximately 1610 UTC, a Grumman AA-5 (registration G-BASG) operating a private flight overran the runway at a grass strip on the Isle of Bute, Strathclyde. The aircraft was destroyed, but neither the pilot nor the sole passenger, a child, was injured.
Aircraft and Pilot
The aircraft, manufactured in 1973, was powered by a single Lycoming O-320-E2G piston engine. The 81-year-old pilot held a Private Pilot's Licence and had 2,419 hours total flying experience, including 152 hours on type. He had flown no hours in the previous 90 days.
Takeoff and Engine Malfunction
The pilot intended a local flight and calculated the aircraft weight at 1,730 lb. For the prevailing conditions, a ground run of 800 feet (244 metres) with 10° flap was required. The wind was light southwesterly at 5 kt, and the air temperature was 16°C.
After taxiing to the threshold of Runway 27, the pilot performed pre-takeoff power checks, which sounded normal. He then selected 10° flap and began the take-off roll using full power. The aircraft accelerated normally but after 50 to 60 metres, witnesses heard the engine running roughly. The rough running continued with increasing misfiring as the aircraft slowly gained speed. Approximately three-quarters of the way along the runway, the pilot closed the throttle and applied the brakes. A witness familiar with departures from the 1% downhill-sloping runway noted that the speed at throttle closure appeared slower than normal.
Overrun
At the end of the runway, a small undulation in the grass surface caused the aircraft to bounce into the air. With subsequent loss of braking, the aircraft overran the runway, struck a fence, slewed left for about 30 metres, and entered a deep ditch. The pilot switched off the fuel and electrics, and witnesses assisted both occupants out of the aircraft.
Pilot's Assessment
The pilot, who had operated the same aircraft from the strip before, concluded that the loss of engine power prevented the normal acceleration of the aircraft.