Pilot Debrief

HUGHES 369D near Carroll Township, PA — 2008-10-30

Final reportERA09LA031
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Date
2008-10-30
Location
Carroll Township, PA, USA
Aircraft
HUGHES 369D
Registration
N606AS
Category
Helicopter
Highest injury
Serious
Fatalities
0
Phase of flight
Maneuvering

Probable cause

A total loss of engine power due to the improper assembly of the compressor discharge tubes to the combustion liner.

NTSB narrative

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.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have inspected for mechanical issues before flight operations began.

NTSB coding

Evidence available

  • Photos
  • 8 docket documents
View NTSB final reportView NTSB docket

Docket documents8

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