Accident Description
Shortly after takeoff, the pilot observed decreasing engine and rotor RPM. He lowered the collective, but the RPM did not return. During the subsequent forced landing attempt, the helicopter collided with trees and terrain.
Investigation
An inspection of the helicopter revealed that the collective pitch push rod (adjustable) had failed in fatigue. The failure resulted in the loss of collective pitch control, preventing the pilot from restoring rotor RPM.
Maintenance History
The last recorded maintenance on the helicopter was performed on February 22, 1988, more than two years prior to the accident. The pilot/owner was operating the helicopter with a student pilot certificate and was carrying passengers at the time of the accident.