What happened
On 21 July 2016, a Schleicher ASW 27-18E (ASG 29E) glider, registration G-VLCC, was involved in a fatal accident near Moundsmere, Hampshire. The pilot, an experienced glider pilot with 1,800 hours of experience, had launched via aerotow from Lasham Airfield with the intention of performing a cross-country task. The flight plan included a period of soaring and a pre-planned practice session to start the aircraft's sustainer engine at a safe altitude.
During the aerotow, the tug pilot noted unusual lateral and vertical movement of the glider at approximately 500 ft, though no radio communication was received from the pilot regarding any issues. After releasing the tow at roughly 2,000 ft, the pilot continued to soar for approximately 21 minutes, during which time she was heard communicating normally on the radio.
However, flight data from the aircraft's FLARM system indicates that after a period of climbing and descending, the aircraft entered a rapid descent. In the final 35 seconds of flight, the glider's descent rate accelerated sharply, reaching over 7,000 fpm. The aircraft entered a spiral dive and struck the ground at a speed exceeding 100 kt. The impact resulted in one fatality and the total destruction of the aircraft.
The investigation
Investigators examined the wreckage and recovered avionics, including a navigation tablet and flight computer. Although the devices were too damaged to recover internal memory, FLARM broadcasts from a ground-based receiver provided a detailed track of the flight. This data confirmed the aircraft's altitude, vertical speed, and turn rate up until the moment of impact.
Engine noise levels were analyzed using logs from previous flights to determine if the sustainer engine had been used. Witnesses on the ground reported hearing an engine that appeared to be stuttering or running up and down, which investigators attributed to the engine's automatic over-speed protection system. No technical failures of the flight controls or the airframe were identified during the examination of the wreckage.
Findings
- The aircraft entered a high-speed spiral dive shortly before impact.
- There was no evidence of any technical failure or control system malfunction.
- The pilot may have been distracted by difficulties integrating a navigation tablet with the flight computer.
- It is possible the pilot experienced sudden incapacitation due to a cardiac event, supported by a known history of heart palpitations and family medical history.
- The engine was likely running during the final descent, with the observed noise fluctuations caused by the over-speed protection mechanism.