Serious incident Bell 412 N22347, Thursday 19 August 2004

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Date:	Thursday 19 August 2004
Time:	07:05 LT
Type:	Bell 412
Owner/operator:	Petroleum Helicopters Inc.
Registration:	N22347
MSN:	36005
Year of manufacture:	1994
Total airframe hrs:	14437 hours
Engine model:	P&W PT6T-3B
Fatalities:	Fatalities: 0 / Occupants: 9
Other fatalities:	0
Aircraft damage:	Minor
Category:	Serious incident
Location:	South Pass 65, - United States of America
Phase:	En route
Nature:	Unknown
Departure airport:	Boothville, LA (1B7)
Destination airport:	VK989, GM
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
The 11,750-hour co-pilot heard a "loud bang" followed by a loss of tail rotor control that produced a 30-degree yaw to the right and a 15-20 degree "nose tuck." Subsequently, the co-pilot reduced power and initiated an autorotation to the water, and prior to touchdown, successfully deployed the emergency floats. The reason for the failure and separation of the tail rotor gearbox could not be determined.

Probable Cause: The failure and separation of the tail rotor gearbox for undetermined reasons.

Accident investigation: