No fatalities

Helicopter Sustains Substantial Damage After Hard Landing; All Six Shearbolts Fail (N24SD)

Rock Springs, WY, US

On September 13, 2005, a Bell 47G-3B-1 (registration N24SD) was involved in an aviation accident near Rock Springs, WY. No fatalities were reported. Investigators recorded the probable cause as: the pilot's failure to maintain control of the helicopter during the attempted autorotation after he experienced an engine overspeed that occurred for reasons undetermined. 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

A pilot reported a grinding noise and yaw, followed by an engine overspeed and autorotation. The helicopter impacted hard, resulting in substantial damage. Examination revealed all six shearbolts failed with shearing signatures.

Accident Details

According to the pilot, the helicopter was maneuvering at approximately 25 feet above ground level when he heard a grinding noise. The helicopter yawed to the right a couple of times. The pilot stated that the engine then began to overspeed, prompting him to initiate an autorotation. The helicopter impacted the ground hard, resulting in substantial damage.

Examination Findings

A post-accident examination revealed that all six shearbolts had failed. Fracture faces of the shear bolts showed signatures consistent with a shearing action. The examination of the helicopter airframe, engine, transmission, and remaining systems revealed no anomalies.

Frequently asked questions

What happened in the 13 Sept 2005 Bell 47G-3B-1 accident near Rock Springs, WY?

A pilot reported a grinding noise and yaw, followed by an engine overspeed and autorotation. The helicopter impacted hard, resulting in substantial damage. Examination revealed all six shearbolts failed with shearing signatures.

Were there any fatalities in the 13 Sept 2005 Bell 47G-3B-1 accident?

No fatalities were recorded in this accident.

What aircraft was involved and where did it happen?

The accident on 13 Sept 2005 involved a Bell 47G-3B-1, registration N24SD, at Rock Springs, WY.

What was the probable cause of the accident?

the pilot's failure to maintain control of the helicopter during the attempted autorotation after he experienced an engine overspeed that occurred for reasons undetermined.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20051007X01601. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.