On September 7, 2001, a Bell 47G (registration N6327D) operated by Mt. Hebron Helicopters was involved in an aviation accident near Berry, AL. Investigators recorded the probable cause as: The failure of the main rotor system stabilizer damper control horn assembly, resulting in an uncontrolled descent and subsequent collision with a tree and terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
While maneuvering at low altitude, a helicopter pilot heard a pop, then lost cyclic control. The helicopter impacted a tree and flipped over. Metal shavings were found near the rotor head stabilator damper horn assembly.
Accident Details
The pilot was maneuvering the helicopter at a low altitude when they heard "a pop or a bang outside the helicopter." While initiating a left turn, the pilot noticed a "mushiness" in the cyclic control, followed by a loss of left and right cyclic control. The pilot attempted to reach a clearing, but the helicopter entered an uncommanded left turn. When the pilot attempted to slow the helicopter using the collective, the helicopter tilted back to the right, impacted a small tree, touched down on its right skid first, and then flipped up onto its nose.
Examination Findings
Examination of the wreckage revealed "ground metal shavings" near the rotor head stabilator damper horn assembly where the control horn attaches to the splined shaft.