Casualties unknown

Helicopter Tour Accident Caused by Fatigue Crack in T-Fitting (N889AT)

Kukuihaele, HI, US

On August 11, 1994, an Aerospatiale AS350-D (registration N889AT) was involved in an aviation accident near Kukuihaele, HI. Investigators recorded the probable cause as: a fatigue crack in the 'T' fitting on the power turbine governor pneumatic accumulator. A factor was the rough, rock-covered landing area. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

During a sightseeing helicopter tour at 1200 feet AGL, the main rotor RPM decreased. The pilot attempted a precautionary landing on a boulder-covered ledge, but the engine failed to respond. Subsequent examination revealed a fatigue crack in a steel T-fitting.

Accident Sequence

A sightseeing helicopter tour was in progress at an altitude of 1200 feet above ground level when the pilot heard a decrease in main rotor RPM. The pilot initiated a precautionary landing toward a boulder-covered ledge located approximately 50 feet from the surf line. When the pilot added power for the landing, the engine did not respond, and the main rotor RPM horn activated. After touchdown, the main rotor and tail rotor blades struck rocks, and the helicopter rolled onto its right side.

Examination Findings

An examination of the engine revealed a fatigue crack in a steel T-fitting. This fitting attached the pneumatic PG accumulator to the power turbine governor. The crack was located in the channel of the fitting where the adjacent nut retention wire was wrapped. A metallurgical examination found no other conditions that may have contributed to the initiation of the crack.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001206X02064. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.