Jabiru UL-D, G-JAAB, 12 September 2007

• From: Air Accidents Investigation Branch
• Published: 10 December 2014

• Category: Sport aviation and balloons
• Report type: Bulletin - Field investigation
• Date of occurrence: 12 September 2007
• Aircraft type: Jabiru UL-D
• Location: Upper Dean, 10 nm north of Bedford, Bedfordshire
• Registration: G-JAAB

Jabiru UL-D, G-JAAB

Summary:

During flight the pilot noticed the sudden onset of vibration from the engine. Whilst on the approach to a field for an emergency landing the engine stopped. Examination of the engine revealed that the No 3 cylinder exhaust valve had failed in fatigue and that the remaining three exhaust valves had fatigue cracks in the same areas as the No 3 valve had failed. The engine had operated for 121 hours since it was manufactured and had Jabiru Service Letter JSL 002-1 titled ‘Jabiru Engine Economy Tuning’ embodied. During this investigation the cylinders and pistons from another Jabiru engine, that had been fitted to a Thruster microlight, were sent to AAIB following a failure of No 1 cylinder exhaust valve. The metallurgical examination of all four exhaust valves indicated a very similar failure mode and fatigue cracking as those from G-JAAB. The engine had operated for approximately 300 hours since it the valves were replaced and had Jabiru Service Letter JSL 002-1 titled ‘Jabiru Engine Economy Tuning’ embodied. Two Safety Recommendations are made to the Australian Civil Aviation Safety Authority.

Download report:

Jabiru UL-D, G-JAAB 05-10.pdf (1,019.87 kb)

Published 10 December 2014