What happened
A Piper PA-31-350, registration C-GVCP, was conducting a scheduled cargo flight from Nanaimo to Comox, British Columbia, when a catastrophic fire occurred. While performing a practice approach to Runway 30, the crew notified the tower of an engine fire in the right engine. Shortly after this emergency declaration, the aircraft was overtaken by flames. At 0741 Pacific daylight time, the aircraft rolled inverted and struck the ground approximately 300 feet short of the runway threshold. The impact caused the aircraft to break apart, and a post-crash fire further destroyed the wreckage. Both crew members were fatally injured.
The investigation
Investigators examined the wreckage and identified molten aluminum debris along the approach path, indicating in-flight burning. The examination of the right engine revealed that the fire originated near the accessory section. Specifically, the gasket for the oil filter converter plate was found to be extremely deteriorated. This failure allowed pressurized engine oil to spray onto hot turbo-charger and exhaust components, initiating the fire.
Further inspection showed that the fire had burned through the wing's leading edge and breached the main fuel tank. Because the firewall fuel shut-off valve had not been closed, pressurized fuel continued to reach the engine-driven fuel pump. The intense heat eventually melted the pump casing, which intensified the fire. The investigation also noted that the aircraft lacked an engine-fire warning system, and the crew did not activate the firewall shut-off valve or feather the propeller, likely due to the high workload of the immediate landing.
Findings
- The primary cause of the fire was the failure of an improper oil filter converter plate gasket in the right engine.
- This specific gasket was part of a known bad batch that should have been removed from service per Airworthiness Directive 2002-12-07.
- The failure to close the firewall fuel shut-off valve allowed continuous fuel delivery, which intensified the fire after the engine-driven fuel pump casing melted.
- The fire breached the main fuel tank, leading to the aircraft being engulfed in flames.
Safety action
Following the investigation, Transport Canada issued a Service Difficulty Alert (AL-2005-08) to notify owners, operators, and overhaul facilities of the hazards. The alert emphasized the need to ensure compliance with AD 2002-12-07, incorporate relevant Lycoming service bulletins, and purge all inventories of the defective gaskets (P/N LW-13388).