What happened
On 1 February 2004, a Piper PA-25-235 Pawnee, registration G-BDWL, was performing a routine aero-tow operation at Crowland Airfield, Lincolnshire. The aircraft was towing a glider as part of a private flight. The takeoff proceeded normally, with the aircraft and glider climbing steadily at approximately 60 kt.
At an altitude of roughly 500 feet, the aircraft unexpectedly began a gentle turn to the right. As the bank angle increased, the rate of climb decreased, and the aircraft entered a descent. The glider instructor, recognizing the abnormal flight path, initiated a release. The glider successfully separated from the tow and returned to the airfield for a safe landing.
The G-BDWL continued its right-hand turn with an increasing bank angle and a steepening descent. Witnesses noted that the engine power remained at takeoff settings throughout the maneuver, with no visible control inputs from the pilot. The aircraft eventually struck the ground at a 4/5 nose-down attitude and a 35-degree right bank, resulting in the fatal injury of the pilot and the destruction of the aircraft.
The investigation
The AAIB investigation focused on the mechanical condition of the aircraft and the health of the pilot. Engineers examined the control systems and found no pre-impact failures. While corrosion was discovered in the right elevator's trailing edge tube, it was determined that this would not have caused the observed flight path deviation.
The pilot was an experienced flyer with over 2,000 hours of experience. Although he held a valid JAA Class 2 medical certificate and had undergone recent cardiological reviews, a post-mortem examination provided critical insight into the event. The pathology report indicated that the crash was likely caused by a sudden medical event involving a hemorrhage into a coronary artery plaque, which likely triggered a cardiac arrhythmia and subsequent loss of consciousness.
Findings
- The aircraft's engine power remained constant during the descent, suggesting no mechanical power loss.
- The glider was released successfully by the crew following the onset of the aircraft's unusual maneuver.
- The pilot likely became medically incapacitated in flight due to a sudden, unpredictable cardiac event.
- The aircraft struck the ground in a steep, nose-down attitude with no apparent pilot intervention.