What happened
On 18 May 2013, a modified Piper PA-18-150 Super Cub, registration G-AWMF, was conducting glider towing operations at Wycombe Air Park, Buckinghamshire. The weather conditions were favorable, characterized by good visibility and light to moderate winds. The aircraft had successfully completed ten consecutive glider tows prior to refueling and was performing its third takeoff following the refuelling stop.
During the initial climb, at an altitude of approximately 50 ft, the aircraft experienced a sudden vibration of such intensity that the pilot was unable to read the flight instruments. This vibration was immediately followed by a total loss of engine power. In response to the emergency, the pilot released the glider and executed a forced landing in a field located beyond the airfield perimeter.
Upon impact with a hedge, the aircraft pitched nose-down and flipped onto its back, coming to rest in an inverted position. The impact caused extensive damage to the airframe and resulted in local soil contamination from spilled fuel. The pilot, who was wearing a full harness, sustained no injuries and was able to exit the aircraft through the door.
The investigation
The investigation was initiated following the submission of an aircraft accident report by the pilot. Investigators examined the circumstances surrounding the flight, noting that the pilot held a National Private Pilot’s Licence and had 257 total flying hours, with 109 hours recorded on this specific type. The investigation focused on the sequence of events leading from the sudden vibration to the complete loss of engine power.