What happened
On 13 February 1998, a Cessna F172L, registration G-AZJV, was conducting a private flight from Gloucester to Cardiff. During the descent from 2,000 feet to 1,400 feet within the Cardiff Control Area, the pilot frequently applied carburettor heat as a precaution against potential icing, though no icing was initially observed.
Approximately four minutes after the descent, the engine power dropped abruptly and smoothly from cruise settings to 800 RPM. The pilot issued a 'Mayday' call and initiated emergency procedures, including switching the fuel selector to the 'both' position. While vigorous manipulation of the throttle produced brief increases in engine RPM, the power could not be sustained. Realising the aircraft lacked the performance to reach the airfield, located 6 nm away, the pilot steered the aircraft away from populated areas and performed a successful forced landing in a nearby field. There were no injuries to the two occupants.
The investigation
Following the incident, emergency services responded rapidly, with a police helicopter arriving at the scene almost immediately. An inspection of the induction system and a flushing of the carburettor were performed by a licensed engineer. These checks revealed no mechanical faults, and the engine subsequently operated normally. The aircraft was able to fly out of the field the next day.
Findings
- The engine failure was likely caused by severe carburettor icing.
- An alternative possibility considered was that a foreign object may have temporarily obstructed the carburettor.