NTSB Identification: DEN01LA106.
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Accident occurred Tuesday, May 29, 2001 in Elizabeth, CO
Probable Cause Approval Date: 02/20/2002
Aircraft: Enstrom F-28C, registration: N83GT
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 instructor was flying the helicopter and giving instruction on steep approaches to the private pilot. During a demonstrated steep approach, they were in translation and at approximately 80 feet above ground level (AGL) when he noticed the rotor and engine RPM start to decay. The student pilot stated that, the instructor was giving him a visual reference between their indicated airspeed, which was approximately 50 MPH, and what the "picture on the ground" looked like. As the instructor continued the descent, the student pilot observed that the engine speed was at approximately 2900 RPM, and the manifold pressure indicated approximately 15 inches. The student pilot heard a change in rotor RPM and noticed that the both the rotor RPM and manifold pressures were dropping. We were "probably at 50 to 75 feet AGL with a visual ground speed of about 10 mph." The instructor stated "we are having an engine failure" lowered the collective control lever and increased the throttle. There was no reaction in manifold pressure and the main rotor RPM continued to decrease. The instructor landed the helicopter in a field just short of the intended landing point. The helicopter hit the ground at a higher than normal descent rate and the main rotor blades struck the tail boom, severing the tail rotor and tail rotor gearbox from the tailboom. Examination of the engine revealed that the idle speed and mixture settings were out of adjustment; however, the cause of the loss of engine power was not determined. The density altitude was calculated to be 7,943 feet msl.

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

the loss of engine power during approach for an undetermined reason. A contributing factor was the high density altitude.

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