What happened
On 15 August 2001, a Piper PA-28-140, registration G-AVLR, departed Cambridge airport for a private flight near Southwold. The weather conditions were favorable, with good visibility and light winds. Shortly after takeoff, the pilot notified air traffic control that he was leaving the circuit.
As the aircraft progressed toward its destination, witnesses noted an unusual, rasping noise coming from the engine. The pilot eventually issued a distress call, reporting a loss of power approximately five miles west of Southwold. He indicated his intention to attempt a forced landing at the disused Halesworth airfield.
During the approach to the landing site, the aircraft was observed at a very low altitude, approximately 300 feet. Witnesses described the aircraft performing a left-hand turn that was yawed and skidding. The aircraft continued its descent through a field of standing crops, eventually striking a hedge. The impact caused the left wing to separate from the fuselage and the aircraft to come to rest upright on that wing. The pilot sustained a fatal injury due to lateral movement within the cabin during the impact.
The investigation
Investigators examined the wreckage and the engine to determine the cause of the power loss. While the airframe and controls were found to be in serviceable condition, the engine revealed a massive internal mechanical failure. Specifically, the big ends of the first two connecting rods had failed due to extreme heat, which had compromised their structural integrity. This failure was consistent with a rapid loss of oil pressure or volume.
Engine inspections showed no evidence of external leaks or pre-impact assembly errors. However, the internal damage to the crankpins and bearings was significant. The investigation also looked into the flight path, noting that the pilot was attempting to navigate between fields of crops and a line of trees and bushes. The aircraft's speed was estimated at 65 knots, which was close to the stalling speed of 56 knots in that configuration.
Findings
- The primary cause of the accident was a massive internal engine failure involving the rupture of two connecting rod big ends.
- The pilot was performing a forced landing at an extremely low altitude, significantly below the recommended 1,000 feet for such maneuvers.
- The aircraft entered a stall during a left-hand turn, likely caused by an attempt to pull up over obstacles or an inadvertent reduction in airspeed while trying to extend the glide.
- The fatal injury was caused by the pilot's upper body sliding sideways out of the diagonal restraint during the high-impact forces of the crash.