NTSB Identification: NYC05LA126.
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Accident occurred Monday, August 01, 2005 in Felton, DE
Probable Cause Approval Date: 04/25/2006
Aircraft: Grumman G-164A, registration: N5495
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

While returning to a private airstrip, the pilot heard a loud explosion from the engine. The engine lost all power, and the pilot performed a forced landing to a soybean field. During the landing, the right wing contacted the ground and the airplane came to rest inverted. The airplane was equipped with a Honeywell (Garrett) TPE331-43A turboprop engine. Examination of the engine revealed that the second stage turbine rotor was fractured, separated, and lodged in the back of the engine. The second stage turbine stator seal plate assembly exhibited warpage. The evidence was consistent with the warped second stage turbine stator seal plate contacting the second stage turbine rotor, causing the rotor to separate. Airworthiness directive (AD) 86-08-06 R1 pertained to the accident engine, and required an x-ray inspection of the second stage turbine stator seal plate assembly. The purpose of the AD was to detect and repair engines with second stage turbine stator seal plate assemblies that exhibited warpage. The last annual inspection of the airplane was performed about 4 months prior to the accident. According to the aircraft logbooks, the airframe and powerplant mechanic with an inspection authorization (IA) noted the AD as not applicable due to engine model number. However, the subject engine model number did require completion of the AD.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The mechanic's inadequate annual inspection, and failure to comply with an airworthiness directive, which resulted in a total failure of the second stage turbine rotor.

Full narrative available

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