Accident Sikorsky S-58F N885, Thursday 16 January 1986

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Date:	Thursday 16 January 1986
Time:	15:05 LT
Type:	Sikorsky S-58F
Owner/operator:	B & G Helicopter Corp.
Registration:	N885
MSN:	58396
Total airframe hrs:	7614 hours
Engine model:	WRIGHT R-1820-84
Fatalities:	Fatalities: 0 / Occupants: 1
Other fatalities:	0
Aircraft damage:	Substantial
Category:	Accident
Location:	North Adams, MI - United States of America
Phase:	Standing
Nature:	Unknown
Departure airport:
Destination airport:
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
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.

Probable Cause:

Accident investigation: