AAIB: Incident report Jabiru UL-450 G-CDFK, 4 April 2023

During the climb after a supposedly normal takeoff, the aircraft did not climb as expected. At 300 feet, the pilot noticed that the engine was not producing full power. With insufficient altitude and speed to return to the runway and no suitable landing sites immediately available, the pilot attempted to remain airborne. Then the engine stopped, the aircraft went into a spin and landed on the ground.

The engine’s loss of power was likely caused by an age-related crack in the rubber coupling that connects the carburetor to the engine’s intake chamber. No problems with the engine were identified during a 100-hour engine service or the subsequent check flight in January 2023. The location of the coupling and its mounting brackets made inspection difficult. The engine manufacturer’s manual stated that the coupling had a lifespan of 1,000 hours, or five years, but there was no evidence that the coupling had been replaced since the aircraft was built in 2006.

The Light Aircraft Association (LAA) is revising its documents to clarify the processes and responsibilities of owners and LAA inspectors in assessing the handling of limited-life components on LAA aircraft.

The UK Civil Aviation Authority (CAA), in addition to the information published in Safety Sense booklets 02, 07 and 12 on stalls/spins and aircraft performance, has hosted a workshop to discuss what to do in the event of an engine failure after take-off and provide some safety advice. They also intend to produce a podcast on engine failure after take-off and a communications campaign to promote the workshop and podcast.

Two safety recommendations have been submitted to the CAA to impose a life limit on the Jabiru carburettor coupling and to consider imposing a life limit on similar components used on other engine and aircraft types.

Read the report.