What happened
On 30 November 2000, a Piper PA60-602P, registration N64719, was performing a private ferry flight from Newcastle to Iceland when it crashed in the vicinity of Fortingall, Perthshire. The aircraft was climbing through FL 140 when the pilot requested a higher altitude to escape icing conditions. Radar data indicated that the aircraft's airspeed and climb rate became increasingly erratic during this period.
At approximately 16:30 UTC, the pilot declared an emergency to air traffic control, stating that the aircraft could not maintain altitude. Shortly thereafter, the pilot reported that while power had been partially restored, the aircraft was no longer controllable. The aircraft entered a rapid descent and a right-hand turn, eventually striking trees and crashing near the base of Drummond Hill. The impact was followed by a significant post-crash fire that destroyed the aircraft and resulted in 1 fatal injury to the pilot.
The investigation
Investigators examined radar data, radio communications, and the wreckage of the aircraft. Although the post-impact fire destroyed much of the airframe and the aircraft's logbooks, the investigation focused on the engine performance and the environmental conditions. Examination of the right engine revealed a failure in the engine-driven fuel pump (EDP) diaphragm, which had been deteriorating over time. This failure likely caused fuel pressure issues.
Analysis of the flight path showed a steady reduction in airspeed while cruising at FL 140, which was consistent with an encounter with icing. The investigation also looked into the state of the de-icing systems and the pilot's decision-making regarding altitude and climb profiles. The investigation noted that the aircraft's center of gravity was near the aft limit, which could have influenced handling during the stall.
Findings
- The aircraft encountered severe icing that likely overwhelmed the de-icing systems and potentially blocked the engine turbocharger inlets.
- A progressive failure of the diaphragm in the right engine-driven fuel pump likely caused an asymmetric power situation or engine starvation.
- The pilot's decision to maintain a lower altitude (FL 140) instead of the planned FL 200 placed the aircraft within a zone of significant icing.
- The aircraft experienced a stall at a speed above the normal stall speed due to the accumulation of ice on the airframe.
- The loss of control was likely a result of a combination of aerodynamic degradation from ice and the engine power imbalance.