NTSB Identification: DEN84FA207.
The docket is stored on NTSB microfiche number 26347.
Accident occurred Monday, July 02, 1984 in ENGLEWOOD, CO
Aircraft: BELL 206B, registration: N3173L
Injuries: 2 Fatal.

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 aircraft accident report.

WITNESSES STATED THE HELICOPTER ENTERED A 'HARD LEFT TURN' INTO A NEAR INVERTED POSITION BEFORE 'IT WENT DOWN HARD AND FAST.' INSPECTION DISCLOSED THE METAL CONNECTION FOR THE LEFT CYCLIC STICK WAS BROKEN IN HALF. (PLT WAS FLYING FROM LEFT SEAT.) EXAM OF THE CYCLIC STICK QUICK DISCONNECT LOCKING NUT REVEALED IT WAS HELD IN PLACE ON THE CONNECTOR BY 1 THREAD. PROPERLY INSTALLED, THE LOCKING NUT TIGHTENS DOWN OVER 6 THREADS ON THE CONNECTOR. WHEN BACKED OUT TO 1 THREAD, MOVEMENT OF THE CYCLIC WILL NOT NOT PRODUCE A CORRESPONDING CHANGE IN THE LATERAL CONTROL HYDRAULIC SERVOS. THE CYCLIC WAS LAST REMOVED APRX 80 HRS PRIOR TO THE ACCIDENT DURING MAINTENANCE. ON 7/17/84, BELL ISSUED OPERATIONS SAFETY NOTICE WHICH IN PART READ, 'FLIGHT CREWS ARE CAUTIONED TO ASSURE QUICK REMOVAL FLIGHT CONTROLS ARE PROPERLY INSTALLED PRIOR TO OPERATING THE HELICOPTER.' PRIOR TO THIS NOTICE, NO REQUIREMENTS EXISTED TO DO SO.

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

ROTORCRAFT FLIGHT CONTROL,CYCLIC CONTROL..DISCONNECTED

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

MAINTENANCE,INSTALLATION..IMPROPER..COMPANY MAINTENANCE PERSONNEL



Contributing Factors

CHECKLIST..INADEQUATE..MANUFACTURER


Contributing Factors

AIRCRAFT PREFLIGHT..INADEQUATE..PILOT IN COMMAND

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