Accident Overview
On 26 June 2018 at 0910 UTC, a Beech A36 Bonanza, registration G-CDJV, sustained damage during a forced landing at Benwick Airstrip, Cambridgeshire. The aircraft, manufactured in 1976 and powered by a single Continental Motors Corp IO-520-BA piston engine, was conducting a private flight with one pilot and one passenger aboard. Neither occupant was injured. The damage included the main landing gear, locker door hinges and ribs, and the propeller.
Sequence of Events
During the takeoff roll, after applying takeoff power, the engine began misfiring. When the pilot reduced throttle, the engine ran more smoothly. Despite the improvement, the pilot assessed that the engine was not operating normally and decided to return to Benwick airfield. While on the left base leg, the engine misfiring resumed. The pilot switched the fuel feed from the left to the right tank, but this did not resolve the misfiring. With the engine producing insufficient power to maintain altitude, the pilot turned immediately toward the runway, extending flaps and lowering the landing gear on short final approach. At touchdown, the undercarriage was still in the latter stages of extension and had not locked into place. During the ground roll, the landing gear collapsed, and the aircraft slid to a halt on its belly.
Post-Accident Examination
After the accident, the pilot recovered approximately 50 cc of dirt-contaminated water from the aircraft’s gascolator, a filter at the lowest point of the fuel system. The pilot had found no evidence of fuel contamination during pre-flight checks. The precise cause of the engine failure could not be determined; however, the owner’s contracted maintenance engineer believed that fuel contamination was a factor. The source of the water in the gascolator was not positively identified.