Accident Overview
The pilot, who was the sole occupant, departed from Biggleswade en route to Audley End to participate in an airshow. During the display, after completing the fourth turn—which was wider than previous ones—the aircraft rolled out on a westerly heading. The pilot reduced the engine rpm on both fixed-pitch propellers to approximately idle. The aircraft then began to decelerate while maintaining straight and level flight with the flaps extended, adopting a progressively more nose-up attitude.
Loss of Control and Crash
At low airspeed, while mid-way along the display axis, the aircraft rolled to starboard and entered a spin to the right from an altitude between 400 and 500 feet. It impacted the ground approximately 300 meters north of the display axis, behind a line of trees that obscured the spectators' view of the impact. The pilot was killed in the accident.
Probable Cause
The official investigation determined the probable cause to be a loss of control at low height after a buckle on the seat belt became entangled with the flying controls.