The failure of an oil filter gasket caused a light aircraft to crash-land in a field near Cookstown, says the official crash report.
The pilot was hurt and a passenger seriously injured.
The Air Accident Investigation Branch said the 1976-built Rockwell Commander, owned by a Yorkshireman, suffered inflight engine failure as a result of “total oil loss” on May 31 last year.
The report said that the 51-year-old pilot, with 526 hours’ flying experience, made a forced landing.
It said: “The aircraft failed to stop before encountering a ditch and hedge at its far end. The aircraft was damaged substantially as it came to an abrupt halt”. The aircraft had been flying from Oban to Abbeyshrule in the Republic and cruising at 2,000ft close to Cookstown.
The report said: “There was a sudden vibration followed by a rapid increase in propeller speed. This was followed by a loud rattling sound from the engine, which then stopped. The pilot reported the entire sequence lasted approximately 10 to 15 seconds.
“He transmitted a ‘mayday’ call to Scottish Information before looking for a field in which to carry out a forced landing.”