What happened
On 21 February 2014, a CEA DR400/2+2 Dauphin, registration G-BBCH, was conducting a local visual flight rules (VFR) mission departing from Gloucestershire Airport. The pilot maintained an altitude between 1,500 ft and 2,000 ft amsl to remain within visual meteorological conditions.
While approximately 10 nm from the airport, the pilot observed a severe drop in engine power. In an attempt to rectify the issue, the pilot applied carburettor heat for roughly 10 seconds, activated the fuel pump, and verified that both magnetos were operational. After notifying air traffic control of the engine malfunction and the intention to perform a forced landing, the pilot attempted to reach a field. However, the aircraft's descent rate increased shortly before contact with the ground, and the plane came to rest in a hedge located in the undershoot area of the intended landing field. The pilot escaped the wreckage without injury, though the aircraft was damaged beyond economic repair.
The investigation
The investigation examined the circumstances leading to the power loss and the pilot's subsequent actions. The pilot noted that during pre-flight preparations, he had not identified a significant risk of carburettor icing. He also indicated that he could not recall using the carburettor heat on a regular basis during the flight.
Following the event, the pilot reviewed CAA Safety Sense Leaflet 14, which details piston engine icing risks. He concluded that the atmospheric conditions during the flight were actually conducive to a moderate to severe risk of icing, which likely caused the engine's power reduction.