On February 29, 1992, a Bell 212 (registration N92AL) operated by Offshore Logistics, Inc. was involved in an aviation accident near Morgan City, LA. Investigators recorded the probable cause as: THE INFLIGHT SEPARATION OF THE MAIN ROTOR SYSTEM AS RESULTS OF THE MAIN ROTOR STATIC STOP CONTACTING THE MAST FOR UNDETERMINED REASONS. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 2 related events involving the same aircraft type or operator are linked below.
An ATP-rated helicopter pilot experienced an inflight breakup at 1,800 feet MSL after control was lost due to mast bumping and main rotor separation. The wreckage was found in a wooded marsh, upside down in about 5 feet of water, with debris scattered over 1,000 yards.
Accident Overview
An airline transport pilot (ATP) rated helicopter pilot was conducting a cruise flight at an altitude of 1,800 feet mean sea level (MSL) when an inflight breakup occurred. The loss of control followed mast bumping, which led to main rotor separation. The main wreckage came to rest in a heavily wooded marsh, inverted in approximately 5 feet of water. Debris and airframe components were scattered across an area spanning roughly 1,000 yards leading up to the main wreckage.
Witness Observation
One witness reported seeing the main rotor system separate from the helicopter's airframe. The main rotor hub, with both main rotor blades still attached, was located about 200 yards from the main wreckage site.
Investigation Findings
Investigators were unable to determine the cause of the mast separation due to the inability to recover a large number of critical components. The missing parts precluded a definitive analysis of the failure sequence.