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Helicopter Experiences Power Loss and Tail Boom Damage During Christmas Tree Lift Operation (N8169J)

Toledo, WA, US

On November 9, 1993, a Bell 47G3B2 (registration N8169J) operated by Farm & Forest Helicopter Svc was involved in an aviation accident near Toledo, WA. Investigators recorded the probable cause as: TRANSMISSION SHEAR BOLTS FAILED CAUSING A LOSS OF POWER TO THE ROTOR SYSTEM, AND THE PILOT ENCOUNTERED UNSUITABLE TERRAIN DURING HIS AUTOROTATION ATTEMPT. 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 2026-07-04Data APIEditorial standards

While lifting Christmas trees under external load, a pilot heard a clunk and experienced power loss. Autorotation from 40-50 feet resulted in tail boom striking a tree. Investigation revealed sheared transmission shear bolts; pilot attributed failure to power impulses from compressor stalls.

Incident Overview

A pilot was conducting external load operations lifting Christmas trees when a clunk was heard and power was lost. The pilot initiated an autorotation from an altitude of 40 to 50 feet, descending into a Christmas tree farm. During the landing, the tail boom struck a tree, causing the tail boom to bend and sustain damage.

Investigation Findings

An investigation determined that the transmission shear bolts, part number 47-620-485-9, had sheared. This mechanical failure was identified as the cause of the power loss that necessitated the autorotation.

Pilot Attribution

The pilot attributed the failure of the shear bolts to power impulses generated by repeated compressor stalls. No other causes or contributing factors were documented in the source.

Frequently asked questions

What happened in the 9 Nov 1993 Bell 47G3B2 accident near Toledo, WA?

While lifting Christmas trees under external load, a pilot heard a clunk and experienced power loss. Autorotation from 40-50 feet resulted in tail boom striking a tree. Investigation revealed sheared transmission shear bolts; pilot attributed failure to power impulses from compressor stalls.

What aircraft was involved and where did it happen?

The accident on 9 Nov 1993 involved a Bell 47G3B2, registration N8169J, operated by Farm & Forest Helicopter Svc, at Toledo, WA.

What was the probable cause of the accident?

TRANSMISSION SHEAR BOLTS FAILED CAUSING A LOSS OF POWER TO THE ROTOR SYSTEM, AND THE PILOT ENCOUNTERED UNSUITABLE TERRAIN DURING HIS AUTOROTATION ATTEMPT.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X13799. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.