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Casualties unknown

Helicopter Engine Failure During Coyote Hunting Operation (N1461W)

Spanish Fork, UT, US

On January 14, 1998, a Bell 47G-3B-2 (registration N1461W) was involved in an aviation accident near Spanish Fork, UT. Investigators recorded the probable cause as: Repeated overspeed of the engine leading to progressive failure of the valve seats and subsequent failure of the valve assemblies, resulting in total loss of engine power. 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

During a low-level coyote hunting flight, a helicopter suffered total engine power loss and collided with trees during a forced landing. Examination revealed progressive valve seat failure due to repeated overspeed.

Accident Overview

A helicopter executing a low-level coyote hunting operation experienced a total loss of engine power while maneuvering. The pilot performed a forced landing to unsuitable terrain, during which the helicopter collided with trees. The accident resulted in damage to the aircraft.

Engine Examination

Post-accident examination of the engine provided evidence of partial failure and/or total failure of the valve assemblies in all cylinders. Laboratory analysis revealed evidence of progressive failure in the valve seats. This condition was indicative of repeated overspeed of the engine.

Findings

The investigatory analysis determined that the progressive failure of the valve seats, consistent with repeated engine overspeed, led to the failure of the valve assemblies and subsequent total loss of engine power. No other contributing factors were identified in the source material.

Probable cause

Repeated overspeed of the engine leading to progressive failure of the valve seats and subsequent failure of the valve assemblies, resulting in total loss of engine power.
Engine failure

Frequently asked questions

What happened in the 14 Jan 1998 Bell 47G-3B-2 accident near Spanish Fork, UT?

During a low-level coyote hunting flight, a helicopter suffered total engine power loss and collided with trees during a forced landing. Examination revealed progressive valve seat failure due to repeated overspeed.

What aircraft was involved and where did it happen?

The accident on 14 Jan 1998 involved a Bell 47G-3B-2, registration N1461W, at Spanish Fork, UT.

What was the probable cause of the accident?

Repeated overspeed of the engine leading to progressive failure of the valve seats and subsequent failure of the valve assemblies, resulting in total loss of engine power.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X09424. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.