History of the Flight
The aircraft, operated by a flying group, was at Tatenhill Airfield for cockpit instrumentation maintenance. The pilot, a 66-year-old with 654 hours total (230 on type), took off at 1410 UTC in good weather, intending to return to Liverpool. At approximately 400 ft agl, power was reduced to climb setting (25 inHg, 2500 RPM). Shortly after, at around 850 ft agl, the engine made a rumbling noise and suddenly lost power. The pilot selected gliding attitude, switched fuel tanks, and checked magnetos, but the engine did not restart. Oil deposited on the windscreen, and a MAYDAY call was made. Another aircraft heard the call and attempted to relay it; contact was eventually established. At about 550 ft agl, the pilot spotted a long field but found it obstructed by transmission lines, then turned to a shorter field. The landing gear remained retracted to reduce rollover risk, and the cabin door was unlatched. After touchdown, the aircraft slid on its belly, entered a copse, and came to a halt. The pilot sustained a left shoulder injury from the control yoke and was later diagnosed with a fractured collarbone. Emergency services were notified via a GPS position, and a police helicopter and air ambulance responded.
Accident Site
The landing occurred on an easterly track in a field approximately 300 m long. The ground was firm with short grass and a gentle downward slope. Touchdown was gentle, with the propeller still turning, and the aircraft initially skipped. About 155 m after touchdown, it entered a small wood. The fuselage passed between two trees, but the wings struck them and were torn off. The aircraft came to rest with the forward fuselage above a stream. No fire occurred. Two pieces of the engine crankcase were found in the field before the touchdown marks.
Aircraft and Engine Examination
The engine, an Avco Lycoming IO-360-C1C (200 shp), was removed and strip-examined. The No 2 connecting rod big-end had separated from the crankshaft. A hole approximately 6 x 8 inches was punched in the upper left crankcase, with both halves fractured and internal components severely damaged. The No 2 connecting rod cap was missing, likely ejected. One big-end bolt was recovered, fractured roughly in half with the nut absent; part of a nut was also found, severely damaged. A portion of the second bolt (head and upper shank) was found in a stream, showing machining damage and over-temperature effects from repeated contact with the No 2 big-end components. Both bolts carried part number SL75060 FAA-PMA. The No 3 and No 4 big-end bolts were adequately torque-tightened (50-55 lb-ft), but damage to the No 2 assembly prevented meaningful torque checks.
Discussion
Materials examination of the least damaged fracture face indicated fatigue cracking involving high tensile stress over a very low number of cycles, consistent with an inadequately torque-tightened nut. The engine had been repaired in late 2002 after metal debris was found in the oil filter, with the crankshaft replaced. It had accumulated about 115 flying hours since. The available evidence, limited by missing parts and damage, did not allow the cause of the engine failure to be positively determined.