What happened
On 14 February 2009, a pilot was conducting solo circuits at Brimpton airstrip near Aldermaston, Berkshire, in a Rans S6-ES Coyote II, registration G-BZYL. The flight was part of a local training session involving specific maneuvers. Following a successful touch-and-go, the pilot intended to execute a tight circuit involving a sharp turn downwind to simulate a problem requiring a quick return to the runway.
During the second circuit, while on the base leg, the aircraft experienced a sudden loss of control. Witnesses observed the aircraft pitch nose-down and the left wing drop, leading to a steep descent. The aircraft rotated through approximately 310° and impacted the ground 140 metres beyond the departure end of the runway. The impact resulted in serious injuries to the pilot and the destruction of the aircraft.
The investigation
Investigators examined the wreckage and analyzed GPS data to reconstruct the flight path. The GPS indicated a ground speed of approximately 40 kt during the climb-out, which, accounting for a light tailwind, suggested an indicated airspeed of roughly 38 kt. This was notably lower than the typical climb speed of 55 to 60 mph.
Technical examination of the Rans S6-ES Coyote II revealed that the engine was delivering significant power at the time of impact, evidenced by the fragmentation of the propeller. The investigation also looked into the configuration of the flaps and carburettor heat. While the post-impact position of the flap lever was not a definitive indicator, evidence suggested some level of flap extension was present. The carburettor heat control was found to be in the hot position.
Findings
- The pilot was likely distracted by planning the upcoming sharp maneuver while on the base leg.
- The aircraft was flying at a speed lower than usual, reducing the margin above the stall speed.
- The high power setting and flap extension likely caused a left wing drop and subsequent autorotation.
- The pilot likely failed to retract the flaps and select cold carburettor heat during the touch-and-go maneuver.