NTSB Identification: NYC93GA151.
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Accident occurred Thursday, August 12, 1993 in GALLIPOLIS, OH
Probable Cause Approval Date: 09/13/1994
Aircraft: ENSTROM F-28C, registration: N51786
Injuries: 1 Serious,1 Minor.
: 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 public aircraft accident report.
THE PILOT ATTEMPTED A PINNACLE TAKEOFF FROM A GRASSY KNOLL. DURING THE TAKEOFF, HE ENCOUNTERED A LOW ROTOR RPM CONDITION IN WHICH THE ENGINE RPM AND MAIN ROTOR RPM DECREASED TOGETHER. THE PILOT SAID HE LOWERED THE COLLECTIVE; HOWEVER, HE WAS UNABLE TO RECOVER THE MAIN ROTOR RPM IN TIME TO PREVENT A FORCED LANDING. HE MADE A RUN ON LANDING IN A GRASSY AREA AND THE MAIN ROTOR AND TAIL ROTOR BLADES STRUCK THE GROUND. THE PASSENGER EXITED THE HELICOPTER WHILE THE MAIN ROTOR WAS STILL TURNING AND HE WAS STRUCK IN THE HEAD BY A BLADE. ACCORDING TO THE FAA BASIC HELICOPTER HANDBOOK, A CONDITION OF LOW ROTOR CAN BE CORRECTED BY REDUCING THE COLLECTIVE WHICH WILL DECREASE THE DRAG ON THE ROTOR, AND THEREFORE, INCREASE THE RPM. ACCORDING TO THE HELICOPTER MANUFACTURER, ONCE THE RPM DROPS BELOW THE NORMAL OPERATING RANGE IT COULD TAKE SEVERAL SECONDS FOR THE RPM TO RECOVER TO THE NORMAL OPERATING RANGE.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's improper use of the collective and throttle which resulted in a low rotor rpm condition and a loss of control, and an inflight collision with the terrain. Full narrative available
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