Piper PA-28-161 Cherokee Warrior II, G-BSPM
During a training flight the aircraft experienced a rapid loss of engine power. The instructor took control and made a forced landing in a ploughed field during which the aircraft became inverted. The loss of power was attributed to a failure of the propeller reduction gearbox due to oil loss from a cracked union on the oil cooler. Analysis of data recorded by the engine’s Full Authority Digital Engine Control (FADEC) unit confirmed that a defect within the propeller system had been apparent prior to takeoff and that the engine had been ‘overspeeding’ shortly after commencing the takeoff. No warnings or cautions were observed by the pilot or instructor until approximately 20 seconds before the loss of engine power.