NTSB Identification: ERA09LA031
14 CFR Part 133: Rotorcraft Ext. Load
Accident occurred Thursday, October 30, 2008 in Carroll Township, PA
Probable Cause Approval Date: 10/21/2010
Aircraft: HUGHES 369D, registration: N606AS
Injuries: 1 Serious.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The helicopter was performing low-level external-load (saw) tree trimming operations when the engine lost power and the helicopter subsequently descended into trees and terrain. Detailed examination of the engine revealed evidence of an improper assembly of the compressor discharge tubes to the combustion liner, and evidence of an improper interim repair. Further metallurgical examination of the combustion section revealed evidence of non-uniform combustion patterns, and a subsequent distortion of the materials, which ultimately resulted in rubbing of the first stage turbine wheel and failure of a turbine blade in high cycle fatigue.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: A total loss of engine power due to the improper assembly of the compressor discharge tubes to the combustion liner. Full narrative available
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