What happened
On 14 February 2001, a pilot was conducting his first solo flight in a Rans S4 Coyote, registration G-MWLY, at Davidstow airfield. The aircraft had been recently purchased and had undergone a flight inspection by another pilot the previous day, which had deemed the aircraft airworthy.
During the takeoff roll on Runway 12, the aircraft became airborne and initially maintained a stable flight path. However, at an altitude of approximately 70 feet, the right wing dropped significantly. Although the pilot managed to level the wings, a second wing drop occurred at 150 feet. This was followed by a roll in the opposite direction, causing the aircraft to enter a left-hand spiral dive that ended in a high-speed impact with the runway. The pilot sustained fatal injuries, and the aircraft was destroyed.
The investigation
The AAIB examined the wreckage and found that the aircraft was at its maximum all-up weight. The investigation focused on the cockpit configuration, noting that the pilot was using a nylon document holder as a cushion to raise his eye line for better visibility. This cushion, combined with the seat being positioned in an aft position to accommodate the pilot's leg length, placed the seat very close to the floor.
Investigators discovered evidence of metal-to-metal contact between the aileron torque tube and the underside of the seat. Specifically, paint had been rubbed off the tube where the pitch trim cable end had been trapped. While it could not be confirmed if a total control jam occurred, the investigation established that the seat design allowed for the possibility of the seat sagging onto the control components if the hang straps were misadjusted or slipped.
Findings
- The pilot lacked a structured transition and training program for this specific aircraft type.
- The pilot's medical condition, including a recent viral infection and the use of an antihistamine, likely reduced his ability to manage the high-stress situation.
- The aircraft was operating at a reduced engine power setting, which may have led to a decay in airspeed and an approaching stall.
- There was a potential for aileron control restriction caused by the seat making contact with the aileron torque tube.
Safety action
- The Popular Flying Association (PFA) was advised to ensure that all UK-registered Rans S4 Coyote aircraft are modified to prevent the seat from collapsing onto the aileron torque tube in the event of strap failure or slippage.