What happened
On 29 March 2009, a Jabiru UL-450 with registration G-CEKM was conducting a private flight from Cromer to Headon. During the final approach, at an altitude of approximately 300 ft QFE, the pilot attempted to increase the throttle, but the engine failed to respond. The pilot then activated the 'hot air' carburettor heat, but the engine stopped shortly thereafter.
The aircraft subsequently touched down short of the intended landing field, striking a hedge at the field boundary. The nosewheel entered a ditch, causing the aircraft to pitch over into an inverted position. The pilot and passenger were able to exit the aircraft through the passenger window without injury. The aircraft sustained substantial damage.
The investigation
The AAIB examined the aircraft's fuel system and found no anomalies. However, investigators discovered a broken electrical lead for the electric carburettor heat system, which rendered that component inoperative. The pilot believed this failure likely occurred prior to the forced landing.
Atmospheric data indicated that the flight took place in conditions favorable for light icing during cruise or descent. The investigation also noted the aircraft's proximity to an operational power station near the River Trent, which can significantly increase local humidity due to cooling towers.
Findings
- The engine failure was likely caused by carburettor icing.
- A broken wire rendered the electric carburettor heat system non-functional.
- The high humidity levels near the power station created conditions conducive to icing.
- The brief use of the 'hot air' carburettor heat during the descent was likely insufficient to melt any accumulated ice.