AAIB investigation to Beech A36 Bonanza, G-CDJV

Landing gear collapse after touchdown, Benwick Airstrip, Cambridgeshire, 26 June 2018.


At takeoff power, on departure, the engine began misfiring but ran more smoothly when throttled back. Despite it sounding better, the pilot assessed that the engine was not running normally and elected to return to Benwick. On left base, the engine started misfiring, so the pilot switched from left to right tank fuel feed. Switching fuel supplies did not cure the misfiring. With the engine delivering insufficient power to maintain height, the pilot turned immediately for the runway, extending the flaps and landing gear on short finals. At touchdown, the undercarriage was in the latter stages of lowering and not locked down. During the ground roll the landing gear collapsed and the aircraft slid to a halt on its belly.

The pilot had found no evidence of fuel contamination during his pre-flight checks but recovered approximately 50 cc of dirt-contaminated water from the aircraft’s gascolator after the accident. While it was not possible to determine the precise cause of the engine failure, the owner’s contracted maintenance engineer believed fuel contamination was a factor. The source of the water in the gascolator was not positively identified.

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Beech A36 Bonanza, G-CDJV 10-18

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Glossary of abbreviations

Published 11 October 2018