What happened
On 30 September 2016, an Auster 5 Alpha, registration G-APAF, was conducting a private flight near Netheravon Airfield in Wiltshire. While the aircraft was at an altitude of approximately 300 ft agl, it was on final approach for landing with the carburettor heat system engaged. During this phase of flight, the engine experienced a loss of power and ceased to respond to the pilot's control inputs.
In response to the engine failure, the pilot performed a forced landing. The maneuver resulted in damage to the aircraft's left landing gear, though no injuries were reported to the crew members on board.
The investigation
Following the incident, the AAIB examined the circumstances surrounding the power loss. The investigation focused on the functionality of the engine's induction system and the pilot's use of the carburettor heat. The pilot reported that the loss of engine power was linked to the state of the carburettor heat system.
Findings
- The engine power loss was attributed to carburettor icing.
- This icing occurred as a direct consequence of a malfunction within the carburettor heat system.