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Helicopter Accident on Hilltop After Engine Failure (N8476E)

Adjuntas, PR, US

On July 29, 1992, a Bell 47J2 (registration N8476E) operated by Western Helicopters, Inc. was involved in an aviation accident near Adjuntas, PR. Investigators recorded the probable cause as: THE FAILURE OF THE PILOT-IN-COMMAND TO MAINTAIN ADEQUATE ROTOR RPM DURING A PRECAUTIONARY LANDING FOLLOWING THE LOSS OF ENGINE OIL. 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.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-07-04Data APIEditorial standards

Witnesses observed a helicopter, then heard a loud bang and the engine went silent. The helicopter turned left, descended, and impacted a hill. Post-crash examination revealed an unlocked oil stick and oil leakage.

Accident Sequence

Witnesses reported observing the helicopter in flight. Subsequently, a loud bang was heard, after which the engine was no longer audible. The helicopter immediately initiated a left turn and began to descend. As it approached the ground, the engine noise increased. The helicopter then impacted hard on top of a hill.

Post-Crash Examination

Examination of the wreckage revealed that the engine and transmission oil tank, as well as the engine oil system, contained 2 quarts of oil. The turn-to-lock type oil dipstick was found not locked. Oil residue was visible exiting the filler neck and flowing out of the engine compartment and down the tail boom. No oil leakage was found on the ground at the crash site.

The day before the accident, an FAA inspector had noted oil leakage in and around the helicopter's engine compartment.

Toxicology Results

Toxicology tests on the pilot were positive for 0.010 ug/mL (blood) tetrahydrocannabinol carboxylic acid (marijuana). One passenger tested positive for 0.038 ug/mL (blood) marijuana, and another passenger tested positive for 2.4 mcg/mL (urine) diphenhydramine (Benadryl).

Related events

Same operator

Frequently asked questions

What happened in the 29 Jul 1992 Bell 47J2 accident near Adjuntas, PR?

Witnesses observed a helicopter, then heard a loud bang and the engine went silent. The helicopter turned left, descended, and impacted a hill. Post-crash examination revealed an unlocked oil stick and oil leakage.

What aircraft was involved and where did it happen?

The accident on 29 Jul 1992 involved a Bell 47J2, registration N8476E, operated by Western Helicopters, Inc., at Adjuntas, PR.

What was the probable cause of the accident?

THE FAILURE OF THE PILOT-IN-COMMAND TO MAINTAIN ADEQUATE ROTOR RPM DURING A PRECAUTIONARY LANDING FOLLOWING THE LOSS OF ENGINE OIL. IN ADDITION, THE PILOT FAILED TO INSURE THAT THE ENGINE CONTAINED ADEQUATE OIL, AND THAT THE OIL DIP STICK WAS SECURE PRIOR TO TAKEOFF. A FACTOR WHICH CONTRIBUTED TO THE ACCIDENT WAS THE…

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Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X15225. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.