OURAY, CO, USA
N724BF
Enstrom 280FX
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."
On August 7, 2001, at 1830 mountain daylight time, an Enstrom 280FX single-engine helicopter, N724BF, sustained substantial damage when it rolled over on its side during a forced landing approximately 7 miles west of Ouray, Colorado. The private pilot and his passenger were not injured. The helicopter was registered to Young's Manufacturing, Inc., of Montrose, Colorado, and operated by the pilot. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The local flight departed a private helipad near Montrose at 1740. In a written statement, the pilot reported that he attempted a "normal to flat approach to land." Prior to the landing, 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 pilot stated that the elevation at the accident site was about 12,000 feet mean sea level. The helicopter was recovered and examined by a helicopter mechanic and the pilot. The mechanic reported that, in a conversation with another pilot who flew the helicopter a few days prior to the accident, that pilot stated that "the helicopter performed fine except for a problem they had with the wastegate assembly." 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 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.
Source: NTSB Aviation Accident Database
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