NTSB Identification: CHI95LA003.
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Accident occurred Monday, October 03, 1994 in DECATUR, IL
Probable Cause Approval Date: 06/19/1995
Aircraft: BELL 47G2, registration: N5193B
Injuries: 2 Minor.

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

THE PILOT STATED THAT AFTER COMPLETING A LINE PATROL, HE MADE A CLIMBING LEFT TURN TO RETURN TO THE AIRPORT. AT APPROXIMATELY 50 TO 75 FEET ABOVE THE GROUND, THE PILOT HEARD A STRANGE SOUND, THE ENGINE BEGAN TO OVERSPEED, AND THE HELICOPTER BEGAN TO DESCEND. HE LOWERED THE COLLECTIVE AND PLACED THE HELICOPTER INTO AN AUTOROTATION TO MAKE A FORCED LANDING ON A ROAD. THE HELICOPTER TOUCHED DOWN HARD AND WAS DAMAGED. A POSTACCIDENT INVESTIGATION REVEALED 13 OF 32 ROLLER SPRINGS INSIDE THE FREEWHEELING UNIT OF THE TRANSMISSION WERE BROKEN CAUSING THE UNIT TO BECOME DISENGAGED.

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

the failure of the roller springs in the freewheeling unit of the transmission which caused the unit to disengage.

Full narrative available

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