Casualties unknown

2004-02-13: Bell 47G-3B-1 (N83702) — Kremmling, CO

Kremmling, CO, US

On February 13, 2004, a Bell 47G-3B-1 (registration N83702) was involved in an aviation accident near Kremmling, CO. Investigators recorded the probable cause as: The pilot's inability to maintain adequate main rotor rpm during an autorotation practice maneuver, which resulted in a hard landing and substantial damage to the helicopter. 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 1781061362Data APIEditorial standards

A helicopter sustaining substantial damage after an unsuccessful recovery from autorotation practice at 800 feet agl due to inadequate main rotor rpm.

What happened

The pilot was conducting flight training maneuvers, specifically practicing autorotations. The incident occurred while the aircraft was operating at an altitude of 800 feet above ground level (agl). During the maneuver, the pilot observed that the main rotor revolutions per minute (rpm) appeared to be insufficient for a successful recovery.

Attempting to transition back to a hover, the pilot found that there was not enough rotational energy available to complete the recovery. Consequently, the aircraft impacted the ground with significant force, resulting in a hard landing. The impact caused substantial damage to the airframe and rotor system.

The investigation

Post-accident examination confirmed the mechanical state of the aircraft consistent with the pilot's account of insufficient rotor rpm during the recovery phase. The extent of the structural deformation was classified as substantial damage, requiring major repair or replacement of components.

Probable cause

The pilot's inability to maintain adequate main rotor rpm during an autorotation practice maneuver, which resulted in a hard landing and substantial damage to the helicopter.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20040225X00238. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.