On July 19, 1997, about 1700 Pacific daylight time, N1105B, a Hughes 269C helicopter, operated by Precision Helicopters, rolled over during a forced landing and was substantially damaged in Yamhill, Oregon. The forced landing was precipitated by a loss of engine power while maneuvering. The commercial pilot was not injured, and his passenger received minor injuries. Visual meteorological conditions prevailed and no flight plan had been filed. The business flight departed from Yamhill and was conducted under 14 CFR 91 as a local sightseeing flight. According to the pilot, in a written statement (attached) sent to the Safety Board: I proceeded with a normal departure. The throttle governor was engaged, the rotor and engine RPM were stable at 3100 RPM, the [manifold pressure] was indicating 26". Shortly after departure I experienced a power fluctuation resulting in an engine failure. I was at 100 [feet above the ground] and about 40 [miles per hour] when the failure occurred. I first attempted to switch the governor off and then back on. I then secondly tried to open and close the throttle which had no effect. By this time I had entered autorotation, the helicopter struck the ground in a tail low attitude. The helicopter then proceeded to roll over and to the right. The engine and airframe underwent a detailed examination and functional test (report attached) by a Federal Aviation Administration aviation safety inspector from Hillsboro, Oregon, on August 8, 1997, at the Chehalem Airpark in Chehalem, Oregon. The examination did not reveal any evidence of preimpact mechanical malfuction, and no abnormal operation was observed during the funtional test of the engine. The FAA inspector stated that: ... the cyclic governor switch may have been inadvertently placed in the... off position or the RPM dial adjusted to or near the 2800 RPM position. The system design allows for RPM drop when turned off in flight. Additionally any time the engine drops below 2800 the governor is automatically taken out of the system. In a situation of having the cyclic switch placed off, the governor correlation would be turned off and the pilot would have to operate the throttle by hand. This transition, if unexpected could easily result in an engine RPM lost situation. The other situation of a low RPM setting at or near 2800, (either inadvertently bumped or incorrectly set) could lead towards RPM drop if collective was added.... No evidence was found to indicate that the cyclic governor switch was inadvertently placed in the off position, or that the RPM was adjusted to or near the 2800 RPM setting prior to impact.