NTSB Identification: CHI86LA067.
The docket is stored on NTSB microfiche number 31780.
Accident occurred Thursday, January 16, 1986 in NORTH ADAMS, MI
Aircraft: SIKORSKY S-58F, registration: N885
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

WHILE ACCOMPLISHING PREFLIGHT SYSTEMS CHECKS WITH THE ENGINE RUNNING AND THE ROTOR SYSTEM ENGAGED THE AIRCRAFT EXPERIENCED A HYDRAULIC HARDOVER. UNCOMMANDED DISPLACEMENT OF THE FLIGHT CONTROLS CAUSED THE AIRCRAFT TO PITCH UP AND LEFT SIMULTANEOUSLY. THE PILOT WAS UNABLE TO REGAIN CONTROL BEFORE THE MAIN ROTOR BLADES STRUCK THE GROUND AND THE AIRCRAFT CAME TO REST ON ITS LEFT SIDE. TESTING OF THE HYDRAULIC SYSTEM COULD NOT DUPLICATE THE PROBLEM. TEARDOWN INSPECTION REVEALED FOREIGN MATERIAL IN THE HYDRAULIC CYLINDERS.

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

ROTORCRAFT FLIGHT CONTROL SYSTEM,PRIMARY SERVO..FAILURE,PARTIAL

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

DIRECTIONAL CONTROL..NOT POSSIBLE..PILOT IN COMMAND

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

ROTORCRAFT FLIGHT CONTROL SYSTEM..EXHAUSTION

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

THROTTLE/POWER CONTROL..UNCONTROLLED..OTHER MAINTENANCE PERSONNEL


Contributing Factors

CYCLIC..UNCONTROLLED..PILOT IN COMMAND


Contributing Factors

COLLECTIVE..UNCONTROLLED..PILOT IN COMMAND


Contributing Factors

MAINTENANCE..INADEQUATE..PILOT IN COMMAND

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