Pilot Debrief

BELL HELICOPTER TEXTRON CANADA 407 near Gulf Of Mexico — 2011-12-01

Final reportCEN12IA096
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Date
2011-12-01
Location
Gulf Of Mexico, USA
Aircraft
BELL HELICOPTER TEXTRON CANADA 407
Registration
N435PH
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

The failure of the compressor section No. 2 bearing due to false brinnelling and fatigue.

NTSB narrative

While maneuvering for a precautionary landing to an oil rig platform because of a chip light indication, the helicopter's engine lost power. The pilot entered an autorotation, called mayday, inflated the helicopter’s floats, and performed a successful water landing. The pilot and passenger were able to exit the helicopter unassisted into a life raft and were picked up within 10 minutes. Examination and disassembly of the engine revealed the No. 2 bearing had failed. Metallurgical examination of the bearing showed the No. 2 bearing outer ring cracked in fatigue due to false brinnelling, which occurs in cases where the bearing is stationary but is subjected to ambient vibration or shock during transport. A spalling area was severe enough to propagate mechanical stress in the outer ring causing the ring to fracture. The engine compressor section was overhauled 2.7 hours before the failure.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have opted for immediate landing after engine chip light illuminated.

NTSB coding

  • Loss of engine power (total) · Enroute
  • Engine Failure Enroute

Evidence available

  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

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