What happened
On 18 August 2012, a Cessna F172H Skyhawk, registration G-CGRE, was conducting an aerial work flight en route from Durham Tees Valley to Old Sarum. Approximately 40 minutes after departing from Durham, the aircraft's engine began to run roughly and subsequently lost power.
In an attempt to maintain engine performance, the pilot applied carburettor heat and set the fuel mixture to the rich position. However, these actions did not prevent the continued loss of power. The pilot subsequently performed a forced landing in a field near Baas Hill, Hoddesdon, in Hertfordshire. The impact caused damage to the aircraft's wings, nose, and engine. Both the pilot and the passenger sustained minor injuries and were able to exit the wreckage without assistance.
The investigation
The investigation examined the aircraft's fuel levels and environmental conditions. At the time of takeoff from Durham Tees Valley, the fuel tanks had been filled to their maximum capacity of 195 litres. Based on the flight duration, approximately 70 litres of fuel should have remained in the tanks at the time of the incident.
Weather analysis revealed that conditions during the flight were such that carburettor icing was a possibility at cruise engine power settings.
Findings
- The engine experienced a progressive loss of power during the flight.
- Atmospheric conditions provided the potential for the formation of ice within the carburettor.
- The aircraft sustained structural damage to the engine, nose, and wings upon impact with the ground.