AAIB Report: Piper PA-23-250 (G-BJNZ), Engine Failure During IFR Flight
During a IFR flight from Le Touquet to Wellesbourne, a Piper PA-23-250 (G-BJNZ) landed in a field near Enfield, London after suffering engine failure
During a flight under instrument flight rules, the pilot observed oil leaking from the aircraft’s left engine, followed by vibration. He shut the engine down but elected to continue the flight towards Wellesbourne. On reaching 2,000 ft, he found he was unable to maintain level flight on one engine and had to land in a field near Enfield.
The investigation found the left engine failed due to a fatigue crack in one of the cylinder barrels. It is likely that the pilot was unable to maintain level flight on the right engine due to a combination of engine wear, which resulted in reduced power, and the prevailing weather conditions. His decision to continue the flight following the engine shutdown was probably influenced by high workload and plan continuation bias.
As a result of the AAIB’s findings, the aircraft’s maintenance organisation has amended its maintenance programme for aircraft fitted with piston engines operating beyond the manufacturer’s recommended overhaul life. This includes a rate of climb air test to detect a loss of engine power output and the introduction of an oil sample analysis monitoring programme.