What happened
On 4 March 2000, a DHC-1 Chipmunk 22 (registration G-BCSB) was performing glider aero tow operations at RAF Cosford. The aircraft, operated by a civilian gliding club, was attempting to tow a single-seat glider to an altitude of 3,000 feet on a grass runway.
During the takeoff run, the aircraft began to deviate from the runway centerline. Witnesses observed the aircraft accelerating normally before it veered toward the left side of the runway. As the aircraft moved into an area of denser vegetation, it became airborne at a high nose attitude. The aircraft subsequently struck a 30-foot telegraph pole, causing the left wing to detach. The aircraft then rolled and impacted the ground in an inverted position. The pilot, a highly experienced instructor and tug master, sustained fatal injuries due to a heart attack.
The investigation
Investigators examined the aircraft's flight controls, engine, and the physical tracks left on the ground. The investigation established that the aircraft's main wheels had moved into the scrub area approximately 90 metres into the takeoff run. While a fatigue crack was found in an exhaust pipe flange that had allowed some gas to leak into the engine bay, toxicology reports showed no significant carbon monoxide levels in the pilot.
Pathological analysis revealed that the pilot had suffered a myocardial infarction. Evidence suggested this cardiac event likely began in the early morning and progressed during the takeoff, leading to his sudden incapacitation. The investigation also noted that the aircraft's inherent tendency to yaw left during takeoff would have been partially mitigated by the prevailing wind, which was blowing from the right.
Findings
- The pilot became incapacitated due to a myocardial infarction during the takeoff roll.
- The aircraft deviated left from the runway heading, moving into an area containing telegraph poles and trees.
- The aircraft struck a telegraph pole at an estimated height of 24 feet, causing structural failure of the wing.
- There were no mechanical failures in the flight controls, landing gear, or braking systems that would have caused the deviation.