CHI07LA018 · Piper PA-46-310P

The pilot reported that after reaching a cruising altitude of 9,000 feet the engine "missed" and the oil pressure, oil temperature, and manifold pressure began to drop. The pilot attempted to fly to the nearest airport maintaining a 500 to 800 foot per minute descent. Unable to make it to the airport, he chose a field in which to land. He stated he cleared the trees, which surrounded the field, and applied flaps to slow the airplane. The field was muddy so the pilot used the emergency gear extension to lower the landing gear so the airplane would not slide into the trees. The airplane touched down and slid approximately 25 feet prior to coming to rest. The airplane sustained substantial damage to the left wing and fuselage. An engine teardown revealed holes in the crankcase near the number four cylinder and that the engine had sustained both thermal and mechanical damage as a result of oil starvation. A hole was noted in the turbine wheel shroud on the hot section of the right turbocharger. There was no data plate, serial number, or model number present on the turbocharger. The turbocharger contained the part number 466304-0003. The oil inlet and outlet fittings were intact and showed no signs of oil leakage. This turbocharger was torn down and inspected. The inspection revealed the turbine wheel shroud had fragmented as a result of a fatigue failure. The back surface of the shaft and wheel assembly contained contact signatures from the shroud. A review of maintenance records showed that both the left and right turbochargers were installed on June 21, 1988. The data plate on the left turbocharger matched the information in the maintenance records. Without a serial number on the right turbocharger, it could not be verified that this was the same one that was installed on June 21, 1998. However, the maintenance logs provided did not contain a record of the turbocharger having been replaced after that date.

Verbatim NTSB analysis and probable cause from the NTSB dataset