NTSB Identification: DEN01LA141.
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Accident occurred Tuesday, August 07, 2001 in OURAY, CO
Probable Cause Approval Date: 07/25/2002
Aircraft: Enstrom 280FX, registration: N724BF
Injuries: 2 Uninjured.
NTSB investigators may have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
Prior to landing the helicopter at an altitude of about 12,000 feet mean sea level, the pilot completed a "power check," and at that time, the engine was able to develop 39 inches of manifold pressure. While on short final, the pilot added power, however, the engine could only achieve 31 inches of manifold pressure. The pilot then executed a forced landing to a grassy area at the top of a slope. Approximately 10 feet agl, the low rotor rpm horn sounded, and the pilot "cushioned the landing with little power." Subsequently, the helicopter slid off the slope, rolled over, and came to rest on its right side. The helicopter was recovered and examined by a helicopter mechanic and the pilot. During the examination, the mechanic found that "the wastegate linkage sheath was in its detent." However, "the sheath took two fingers with very light pressure to pull it out of its detent." The mechanic attributed the ease with which he was able to pull the sheath out of the detent to "the ball plunger on the wastegate linkage not being torqued." In the mechanic's opinion, "between the light torque on the ball plunger and the heat in the engine compartment, the sheath for the wastegate linkage would at times slide on the inside shaft. Without collective, throttle, and wastegate rigging working together, this would greatly affect power or lack of power."
The National Transportation Safety Board determines the probable cause(s) of this accident to be: the partial loss of engine power due to the slippage of the wastegate linkage as a result of the plunger on the linkage being undertorqued by an unknown person. A contributing factor was the lack of suitable terrain for the forced landing. Full narrative available
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