NTSB Identification: WPR09LA261
14 CFR Part 91: General Aviation
Accident occurred Monday, May 25, 2009 in Ogden, UT
Probable Cause Approval Date: 05/11/2010
Aircraft: ENSTROM HELICOPTER CORP 280C, registration: N5699N
Injuries: 2 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

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.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

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.

Full narrative available

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