Ogden, UT, USA
N5699N
ENSTROM HELICOPTER CORP 280C
The pilot reported that just after passing through takeoff translational lift, he noticed that the reciprocating engine was being over-boosted and that the main rotor blade RPM was drooping. He therefore lowered the collective in an attempt to lower the boost and to regain main rotor rpm, but the helicopter began to sink at a rate that made it necessary for him to immediately transition to a landing. After touching down on the ground, the skids partially collapsed, the helicopter pitched forward, and the main rotor blades flexed downward far enough to sever the tail boom. According to the pilot, the engine seemed to be running strong and smooth, and there did not appear to be any problems with the flight control system. No anomalies were found during a post-accident inspection of the airframe, nor during the engine test run.
On May 25, 2009, about 1200 mountain daylight time, an Enstrom 280C helicopter, N5699N, impacted the terrain during an attempted precautionary landing just after taking off from Hinckley Airport, Ogden, Utah. The private pilot and his passenger were not injured, but the helicopter, which was owned and operated by the pilot, sustained substantial damage. The local 14 Code of Federal Regulations Part 91 personal pleasure flight was taking place in visual meteorological conditions. No flight plan had been filed. According to the pilot of the reciprocating engine helicopter, just after he passed through translational lift he noticed that the engine was being over-boosted and that the main rotor blade RPM was drooping. He therefore lowered the collective in an attempt to lower the boost and to regain main rotor rpm, but the helicopter began to sink at a rate that made it necessary for the pilot to immediately transition to a landing. After touching down on the ground, the skids partially collapsed, the helicopter pitched forward, and the main rotor blades flexed downward far enough to sever the tail boom. According to the pilot, the engine seemed to be running strong and smooth, and there did not appear to be any problems with the flight control system. A Federal Aviation Administration Inspector inspected the helicopter and monitored a post-accident test run of the engine, and he reported that there were no anomalies with either the airframe or the engine.
The pilot's improper use of the helicopter's collective both during the takeoff sequence and while attempting remedial action in response to an engine over-boost condition, which resulted in a hard precautionary landing.
Source: NTSB Aviation Accident Database
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