The Lycoming O-360 engine of a four-seat MS.893A Rallye light aircraft which failed during a ferry flight from Moruya to Archerfield, resulting in a forced landing and serious injuries to the pilot, had not been overhauled in more than two decades.
The ATSB’s investigation report from the 6 November 2020 accident details that the pilot experienced a catastrophic engine failure when they were about 37 km from their destination. With their forward visibility reduced due to engine oil over the windscreen and smoke created by escaping oil on the exhaust system, the pilot force landed in a paddock, with the aircraft striking trees.
Witnesses found the unconscious pilot had been thrown from the aircraft and moved them to safety before the aircraft was consumed by a post-impact fire.
“The ATSB’s investigation found the separation of the number 2 piston connecting rod initiated a catastrophic mechanical failure of the engine,” ATSB Director Transport Safety Dr Stuart Godley said.
The engine had not been overhauled since 1997, and had had limited usage for an extended period, possibly with no specific engine preservation done while in storage.
“Had the engine been overhauled at the manufacturer’s recommended calendar time, the connecting rod journal bearings would have been replaced with post-modification bearings,” Dr Godley said.
“This accident highlights the need for owners and maintainers to be cognisant of the manufacturer’s service information, to ensure the serviceability of engine and airframe systems are maintained to the highest standards.”
In addition, the pilot had been ferrying the aircraft on behalf of the owner and had limited aircraft type experience and knowledge of its performance capabilities.
“The pilot was unaware of the aircraft’s slow speed performance capability, a full understanding of which capability may have been beneficial when responding to the engine failure and forced landing,” Dr Godley said.
The investigation also found that the aircraft was not fitted with a fixed or portable emergency locator transmitter, and that the pilot did not leave a flight note with a responsible person.
“Fortunately the forced landing occurred in a populated area and there were witnesses to the accident who were able to render assistance and call emergency services,” Dr Godley said.
Read the full report here