Casualties unknown

1988-11-10: Bell 206L (N16619) — Air Center Helicopters, Inc. — St. Thomas

St. Thomas, US

On November 10, 1988, a Bell 206L (registration N16619) operated by Air Center Helicopters, Inc. was involved in an aviation accident near St. Thomas. Investigators recorded the probable cause as: A contained failure in the engine compressor section caused a loss of power during flight transition, and the emergency float deployment system failed to function because the electrical wires for the discharge agent separated upon impact with the water. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 10 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A helicopter crew performed an autorotative landing into water following an engine failure, but the aircraft sank after the emergency floats failed to deploy.

What happened

While transitioning from forward flight to a hover, the pilot experienced a loss of power in the helicopter. The pilot performed an autorotation and landed the aircraft into the water. Although the emergency floats were armed at the time of landing, the pilot was unable to deploy them. The pilot and passengers successfully evacuated the aircraft before the helicopter sank.

The investigation

An examination of the wreckage revealed that the electrical wires responsible for activating the discharge agent had separated upon impact, which rendered the float deployment system inoperable. Regarding the engine, investigators found that the compressor section had sustained a contained failure.

Technical analysis showed no evidence of foreign object ingestion, no failure or malfunction of the number 1, 2, or 2.5 bearings, no rubbing of the rotor blades against the compressor case, and no axial movement of the rotor assembly. A metallurgical examination was conducted, but it could not determine the specific event that caused the failure in the compressor section.

Findings

Investigators determined that company personnel were not performing the salt water contamination removal procedure as recommended by the engine manufacturer.

Probable cause

A contained failure in the engine compressor section caused a loss of power during flight transition, and the emergency float deployment system failed to function because the electrical wires for the discharge agent separated upon impact with the water.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X27300. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.