What happened
On 11 October 2009, a student pilot was conducting solo training circuits in a Montgomerie-Bensen B8MR, registration G-BIPY, at Little Rissington Airfield. After successfully completing an initial circuit, the pilot commenced a second circuit. During the base leg of this second circuit, the aircraft deviated from its expected flight path, flying past the point where a descent should have begun and heading toward a noise-sensitive area.
An instructor, observing from a nearby vehicle, attempted to contact the pilot via radio. Shortly after this communication, the autogyro began a sudden, steep nose-down pitch and entered a tumbling descent. The aircraft struck the ground in a near-vertical manner in a field approximately 250 m from the airfield boundary. The pilot, a highly experienced former professional jet pilot, sustained 1 fatality due to the impact forces.
The investigation
The AAIB examined the wreckage and the engine of the G-B/BIPY. The investigation found no evidence of any pre-existing structural or flight control failures. The engine was found to have been delivering power at the time the rotor blades struck the propeller. The investigation also noted that the aircraft's stone-guard/stabiliser had been removed by the pilot on the morning of the accident, though it was determined that this removal would not have significantly altered the handling characteristics.
Investigators also considered the pilot's medical history, noting a pre-existing condition involving irregular heartbeats. While such an episode could have caused distraction or temporary incapacitation, there were no physical signs in the autopsy to confirm such an event had occurred during the flight.
Findings
- The aircraft experienced a loss of control during the second circuit, which may have been a Power Push Over (PPO) resulting from longitudinal instability.
- The pilot may have reacted to a deviation in flight path with an instinctive, inappropriate control input following the instructor's radio call.
- Increasing wind speeds and potential turbulence in the circuit may have contributed to the initial flight path deviation.
- The pilot's extensive experience in large, fixed-wing aircraft may have influenced his instinctive reactions to the sensitive controls of the autogyro.