What happened
On 5 July 2015, a X’air Falcon 133, registration G-CCSO, was conducting a private flight at an altitude of approximately 1,100 ft. While en route to Sandtoft Airfield, the aircraft's engine began running roughly on a single cylinder. Simultaneously, the oil pressure gauge dropped to zero, and the engine ceased operation.
Recognising the loss of power, the pilot identified a field containing a standing wheat crop as a suitable site for an emergency landing. To mitigate the risk of the aircraft overturning upon impact with the crop, the pilot chose to stall the aircraft at a height of roughly 5 ft. The resulting heavy landing resulted in substantial damage to the fuselage and the landing gear. The pilot was able to vacate the aircraft safely without injury.
The investigation
The AAIB investigation focused on the sudden loss of engine power and the drop in oil pressure. The engine, a Verner 133M piston engine, had only completed approximately 40 hours of operation since its installation. Based on the observed symptoms, the pilot suspected a failure of the crankshaft. The investigation noted that this specific engine was one of the earlier models featuring a two-crankshaft bearing design, a version that was later replaced by a more robust three-bearing configuration.