AAIB Report: Jabiru UL-450, G-CDFK, on 4 April 2023
Report into an accident involving a Jabiru UL-450 (G-CDFK), loss of power shortly after takeoff with subsequent stall and spin, Damyns Hall Aerodrome, Upminster, Essex, 4 April 2023
Split carburettor coupling from G-CDFK
During the climb after what was thought to be a normal takeoff the aircraft did not climb as expected. When at 300 ft, the pilot identified that the engine was not developing full power. With insufficient height or speed to return to the runway, and no suitable landing sites immediately available, the pilot attempted to remain airborne. The engine then stopped, the aircraft stalled and entered a spin before striking the ground.
The loss of engine power was probably caused by an age-related split in the rubber coupling attaching the carburettor to the engine’s plenum chamber. No issues with the engine were identified during a 100-hour engine service or the subsequent check flight, carried out in January 2023. The location of the coupling and its mounting clips made inspection problematic. The engine manufacturer’s manual for the engine stated that the coupling had a 1,000 hour, or five-year life but there was no evidence that the coupling had been replaced since the aircraft had been built in 2006.
The Light Aircraft Association (LAA) are revising its documents to clarify the processes and responsibilities of owners and LAA inspectors to make judgements about the management of life-limited components on LAA aircraft.
The UK Civil Aviation Authority (CAA), in addition to the information published in Safety Sense Leaflets 02, 07 and 12 regarding stall/spin awareness and aircraft performance, have hosted a workshop to discuss what to do in the event of an engine failure after takeoff and provide some guidance on staying safe. They also intend to produce a podcast about engine failures after takeoff and a communication campaign to promote the workshop and podcast.
Two Safety Recommendations have been made to the CAA to mandate a life limit for the Jabiru carburettor coupling and consider mandating a life limit for similar components used on other engine and aircraft types.