The Australian Transport Safety Bureau (ATSB) yesterday issued a warning over perishable seals after an engine fire led to the fatal crash of a Mooney at Luskintyre.
VH-UDQ was being flown on approach to Luskintyre Airfield in October 2022 when the engine caught fire. The pilot attempted an emergency landing on runway 30, but the aircraft crashed short of the field after striking trees. The pilot survived the impact, but died of injuries related to the post-impact fire 10 weeks later.
“The ATSB investigation determined fuel leaking from an age-affected O-ring seal of the engine-driven fuel pump ignited and caused an engine compartment fire,” said ATSB Chief Commissioner Angus Mitchell.
“A leak from the pump outlet fitting that supplied the engine fuel control unit was identified, and analysis indicated the O-ring sealing that fitting had deteriorated with age.”
According to investigators, the engine in UDQ had last been overhauled in 1993 and was operating on condition because it had expired on calendar. This means the engine had not been overhauled in 29 years.
The crash has prompted the ATSB to issue safety advisory notice SAN AO-2022-049-001, which draws attention to proactively replacing O-ring seals fitted to engines and engine components that have been in service for a significant period.
“Inspect the uninspected,” Mitchell said.
“If aircraft records identify elastomer–rubber-based–type components that have remained undisturbed for significant periods of time, take a proactive approach – replace components such as O-ring seals before they deteriorate to the point of failure.”
In response to this accident, CASA proposed to review AWB 02-001 relating to on-condition maintenance, and AWB 85-004 regarding aircraft piston engine calendar time overhaul.
The full investigation report is on the ATSB website. A video outlining the incident is also available on You Tube.