What happened
On 10 July 2010, a Stampe SV4C (registration G-BIMO) departed White Waltham Airfield for a local private flight. The aircraft was occupied by two individuals, both of whom held Private Pilot Licences. During the flight, the aircraft performed several climbing turns before the crew attempted a rolling aerobatic manoeuvre.
Digital video footage from a helmet-mounted camera captured the sequence: the aircraft pitched nose-down, accelerating to 110 kt at 3,400 ft, before pitching nose-up. As the aircraft rolled past the inverted position, it departed controlled flight. The aircraft entered an inverted spin that lasted for approximately 37 seconds and encompassed eight turns. The aircraft eventually struck treetops in a woodland area near Rotherfield Peascod at a steep angle, leading to the destruction of the aircraft and two fatal injuries.
The investigation
The AAIB investigation utilised video evidence, eyewitness accounts, and radar data. Examination of the wreckage showed the aircraft was structurally intact at the moment of initial impact with the trees. The investigation found no evidence of technical defects or engine failure that could have contributed to the accident. The fuel system, which used a 'flop tube' to ensure consistent delivery, was found to be functional.
Investigators also reviewed the pilots' experience. While the owner had completed differences training for the Stampe and had performed various aerobatic manoeuvres like loops and rolls, he had not yet been trained in aileron rolls. The investigation also noted that while the occupants wore Kevlar helmets, one helmet lacked the foam liner designed to reduce impact deceleration.
Findings
- The accident was caused by an unsuccessful attempt to perform a rolling aerobatic manoeuvre, which led to the aircraft entering an inverted spin.
- The inverted spin was highly disorientating, making recovery extremely difficult for a pilot with limited aerobatic experience.
- The aircraft's flight path became 'spooned' during the roll, leading to the loss of control.
- There were no mechanical or technical failures identified in the engine or flight controls.