NTSB Identification: ATL82DA027
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Saturday, January 02, 1982 in CHAMBLEE, GA
Probable Cause Approval Date: 01/02/1983
Aircraft: BELL 206L-1, registration: N5745Y
Injuries: 1 Uninjured.

WHILE RETURNING TO REFUEL FROM AN AIR AMBULANCE FLIGHT THE HELICOPTER YAWED LEFT AND N2 DROPPED TO ABOUT 92% APPROXIMATELY ONE MILE FROM THE AIRPORT. AT 30-50 FEET WITH AIRSPEED AT ABOUT 20 KNOTS THE AIRCRAFT YAWED VIOLENTLY TO THE LEFT WITH CORRESPONDING DROPS IN N2 TO 55-60% THEN SURGED BACK TO 102-105%. THE PILOT ENTERED AUTOROTATION AND TOUCHED DOWN HARD 300 YARDS SHORT OF HIS INTENDED LANDING POINT. DETROIT DIESEL ALLISON COMMERCIAL ENGINE BULLETIN(CEB) A-73-2020 DATED 9/7/81 & REVISED 10/5/81 ADVOCATES DISARMING THE N2(ELECTRONIC) OVERSPEED CONTROL SYSTEM BECAUSE OF REPORTED INTERMITTENT AND SPURIOUS ACTIVATION OF THAT SYSTEM. THE SYSTEM WAS ONLY PARTIALLY DEACTIVATED IN COMPLIANCE WITH BELL ALERT SERVICE BULLETIN(ASB) 206L-81-24 DATED 9/11/81 DUE TO THE OPERATOR'S MAINTENANCE PERSONNEL REPORTING THAT THEY HAD NOT RECEIVED THE REFERENCED CEB AS OF THE DATE OF THE ACCIDENT.

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

MAINTENANCE,SERVICE BULLETIN/LETTER..NOT RECEIVED..COMPANY MAINTENANCE PERSONNEL


Contributing Factors

FUEL SYSTEM,FUEL CONTROL..ERRATIC


Contributing Factors

ACFT/EQUIP,INADEQUATE AIRCRAFT COMPONENT..MANUFACTURER



Contributing Factors

LIGHT CONDITION..DARK NIGHT

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