What happened
On 30 December 2000, a Piper PA-28R-200B, registration G-AZRV, was conducting a private flight from Blackbushe to Compton Abbas Airfield. After a routine departure and climb to 2,500 feet, the pilot experienced a sudden increase in propeller RPM. Shortly thereafter, the engine oil pressure dropped to zero.
Recognizing the imminent risk of engine seizure, the pilot attempted to return to the airfield. Due to snow on the ground, assessing landing conditions was difficult. During the approach, the engine seized completely, causing the aircraft to land short of the runway. The aircraft crossed a road and struck a hedge at the airfield's western perimeter, causing the aircraft to be damaged beyond repair. Both the pilot and the passenger sustained serious injuries.
The investigation
The AAIB examined the engine and found a catastrophic failure where the top of the crankcase had ruptured. The investigation established that the No 2 connecting rod big end had failed and the No 1 big end bearing showed signs of extreme heat and imminent failure, with almost no oil remaining in the sump.
Investigators discovered that a replacement engine had been installed just eight days prior. The engineer had fitted a Curtiss CCB-37000 quick drain valve, which was an unapproved part for this specific aircraft/engine combination. This particular valve featured a hose connector that protruded further than the approved version. Marks on the valve's connector suggested it had been struck by the nose landing gear drag linkage during gear retraction, which pushed the valve open and allowed the engine oil to drain away.
Findings
- The engine failure was caused by the loss of oil through an unapproved quick drain valve.
- The nose landing gear drag linkage made contact with the valve's protruding connector during retraction, causing the valve to open.
- The engineer was unaware of a long-standing Airworthiness Directive regarding the specific part number required for the drain valve.
- The engineer relied on a parts distributor's catalogue rather than the specific requirements of the maintenance manual for this task.
- While warning placards were present on the airframe, the engineer had not noticed them.
Safety action
- Safety Recommendation No 2001-59: New Piper Aircraft Corporation should review the Maintenance Manuals for PA-28R series aircraft to ensure adequate warnings are provided across all applicable models regarding the consequences of installing incorrect quick drain valves.