NTSB Identification: DEN88GA088.
The docket is stored on NTSB microfiche number 35679.
Accident occurred Monday, March 21, 1988 in GOBERNADOR, NM
Probable Cause Approval Date: 04/25/1989
Aircraft: BELL 47G-3B1, registration: N7863S
Injuries: 1 Uninjured.

: NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this public aircraft accident report.

THE COMMERICAL PLT WAS HOVERING OUT OF GROUND EFFECT AT 40 FEET AGL. DURING A MANEUVER HE REPORTED HEARING A LOUD BANG AND THE ROTOR RPM BEGAN TO DECAY. THE PLT MADE A HOVERING AUTOROTATION RESULTING IN A HARD LANDING. THE MAIN ROTOR STRUCK THE TAIL BOOM AND SEVERED IT. A POST ACCIDENT TRANSMISSION TEAR DOWN REVEALED THAT THE LOCKING ROLLERS IN THE FREE WHEELING UNIT HAD WORN BEYOND TOLERANCE, ALLOWING THE MAIN ROTOR TO BECOME AND REMAIN DISENGAGED FROM THE TRANSMISSION.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

ROTOR DRIVE SYSTEM,FREEWHEELING SPRAG UNIT..WORN

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

ROTOR RPM..NOT MAINTAINED..PILOT IN COMMAND

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

ROTOR DRIVE SYSTEM,FREEWHEELING SPRAG UNIT..DISENGAGED



Contributing Factors

FLIGHT CONTROLS..IMPROPER USE OF..PILOT IN COMMAND

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