What happened
On 9 July 2009, a Schempp-Hirth Discus B glider, registration G-CHOM, was involved in a fatal accident west of Gransden Lodge Airfield, Cambridgeshire. The flight, a private soaring mission, began with a winch launch that witnesses described as textbook. Following the launch, the aircraft soared for approximately ten minutes.
During the flight, the aircraft was observed by an airborne instructor to be in a left-hand spin. The glider subsequently struck a field of rape, resulting in the fatal death of the pilot. The impact occurred with a relatively low forward speed, and the aircraft came to rest in an upright position. Although the pilot was a highly experienced former commercial jet pilot, no distress call was transmitted via radio prior to the impact.
The investigation
The AAIB examined the wreckage and recovered a Garmin II Plus GPS from the aircraft. While the GPS provided track and groundspeed data, it did not record altitude information for the period immediately preceding the accident. Analysis of the wreckage showed damage to the left wing and tail section consistent with a left-hand spin. The aircraft's controls were found to be fully serviceable.
The investigation also reviewed the aircraft's weight and balance. The centre of gravity (CG) at the time of the accident was calculated to be at the aft limit. While a discrepancy in the aircraft's weight and balance records was identified, it was determined not to be a causal factor in this specific event.
Medical evidence was also considered. Although the postmortem examination found no definitive pathological evidence of a medical event, the investigation noted the pilot's history of a heart condition that could potentially cause an incapacitating abnormal heart rhythm without leaving physical traces.
Findings
- The glider entered a left-hand spin from which it did not recover.
- There was no identifiable mechanical failure or malfunction that caused the spin.
- The pilot's centre of gravity was at the aft limit of the permissible range.
- There was no evidence to confirm whether the spin was intentional or unintentional, though there was no evidence of a planned manoeuvre.
- The possibility of sudden medical incapacitation due to an abnormal heart rhythm could not be entirely ruled out.