A Grob 115E Tutor aircraft, operated by the Royal Air Force (RAF), was undertaking a cadet air experience flight from RAF Benson. The visibility was good and the aircraft was conducting aerobatics, in uncontrolled airspace, when it collided with a glider. The left wing of the Tutor struck the fin of the glider causing the tail section to break away. The glider pilot parachuted to safety. The Tutor entered a spiral / spinning manoeuvre before diving steeply into the ground. The Tutor pilot and cadet were both fatally injured.
The Tutor pilot had a long term medical condition which restricted the movement of his head and affected his ability to conduct an effective look-out; this condition also made him more vulnerable to impact fractures of the spine. Following the collision it is probable that the Tutor remained controllable, suggesting that the pilot had become incapacitated.
The cadet’s harness had been released and the canopy operating handle had been moved to the open position before the Tutor impacted the ground. The canopy jettison mechanism had not been operated.
The accident was notified to the Air Accidents Investigation Branch (AAIB) at 1350 hrs on 14 June 2009 and an AAIB field investigation was commenced immediately. The investigation was conducted by:
Mr P Claiden - Investigator-in-charge
Mr A Blackie - Operations
Mr B D McDermid - Engineering
Mr M Ford - Flight Data Recorders
The investigation identified the following causal and contributory factors:
- Neither pilot saw each other in sufficient time to avoid the collision.
The Tutor pilot’s medical condition, Ankylosing Spondylitis, limited his ability to conduct an effective look-out.
The high density of traffic, in an area of uncontrolled airspace, increased the risk of a collision.
Thirteen Safety Recommendations have been made.
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Published 10 December 2014