Piper PA-28R-200B G-AZRV Accident at Compton Abbas Airfield

Accident Overview and Flight History On 30 December 2000 at 1436 hrs, a Piper PA-28R-200B, registration G-AZRV, was involved in an accident at Compton Abbas Airfield, Wiltshire. The aircraft, manufactured in 1971 and powered by a single Lycoming 10-360-C-IC piston engine, was on a private flight with one crew member and one passenger aboard. Following an uneventful flight from Blackbushe, the pilot conducted a pre-flight inspection, including a satisfactory check of the engine oil contents. The aircraft departed normally, but approximately five minutes later, at an altitude of about 2,500 feet above mean sea level, the propeller rpm suddenly increased. The pilot attempted to retard the propeller pitch control lever without effect and then observed that the engine oil pressure gauge indicated zero, despite having been normal during the climb. ## Engine Failure and Crash Sequence Realizing the engine was likely to seize, the pilot turned the aircraft back toward Compton Abbas and reduced engine power to 20 inches of manifold pressure. Snow on the ground made obstacle identification and field conditions difficult to assess, leading the pilot to attempt a landing on the airfield. The engine subsequently seized, causing the aircraft to land short of its intended point. It carried on across a road before being brought to an abrupt halt by a low bank within a hedge forming the western perimeter of the airfield. The impact caused substantial damage to the underside of the aircraft, which was damaged beyond repair, and probably contributed to the severity of the occupants' injuries. Both the crew member and passenger sustained serious injuries. ## Maintenance Background and Investigation Findings A few days before the accident, the engine had been replaced with a factory-overhauled unit, with installation completed on 22 December 2000. Two running-in flights of approximately one hour each were conducted on 27 December, after which the oil filter was renewed and inspected, found satisfactory. The accident flight was the next operation. Following the accident, the operator and the licensed aircraft engineer who performed the engine change became aware of an FAA Airworthiness Directive regarding the fitment of engine oil quick drain valves. The engineer realized that the drain valve he had fitted was not approved by the aircraft manufacturer for this engine/airframe combination. ## Root Cause and Safety Recommendations On-site inspection revealed a catastrophic engine failure with the top of the crankcase ruptured open, exposing internal components. The No 2 connecting rod big end had failed, and the No 1 big end bearing appeared to be in a condition of imminent failure, with considerable heat generated and virtually no oil remaining in the sump. Examination of the engine and drain valve showed the quick drain valve was in the closed position, but a flake of engine debris was embedded in the valve, indicating it must have been open at some stage while the engine was running in its damaged condition. The investigation determined that the engine failed as a result of oil loss caused by the fitting of an unapproved quick drain valve to the sump. Previous incidents had indicated that the nose landing gear drag linkage could contact the valve's hose connector on gear retraction, moving it upwards and opening the valve. The pilot held a Private Pilot's Licence, was 43 years old, and had 465 hours of flying experience, including 105 hours on type. In the last 90 days, he had 16 hours, and in the last 28 days, 3 hours. As a result of the investigation, Safety Recommendation No 2001-59 was addressed to New Piper Aircraft Corporation, recommending a review of the Maintenance Manuals for PA-28R series aircraft regarding the installation of quick drain valves to provide adequate warnings of the consequences of fitting an incorrect valve for all applicable model types. The UK CAA indicated it would include this accident in a forthcoming issue of their General Aviation Safety Information Leaflet (GASIL).