NTSB Identification: SEA05LA120
14 CFR Part 91: General Aviation
Accident occurred Friday, June 17, 2005 in Billings, MT
Probable Cause Approval Date: 10/27/2005
Aircraft: MBB BO-105, registration: N314MS
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 pilot had just finished giving the other pilot a proficiency check, and had then taken control of the aircraft so that he could perform some maneuvers for his own proficiency. He performed one simulated engine-out autorotation to a touchdown, and was completing his second, when the accident occurred. He initiated the autorotation from about 1,000 feet above the ground (agl), and began establishing a flare attitude at an altitude of 100 feet agl. At that time he noticed that the descent rate of the helicopter was excessive, but instead of adding power along with the increase in collective, he decided to continue the simulation of the power loss. Just prior to touchdown, the pilot established a landing attitude and used all of the available collective to cushion the landing. When the helicopter touched down, the descent rate was still greater than the pilot desired, and immediately after contacting the ground, the main rotor flexed downward and contacted the top of the tail boom. The pilot reported that there were no problems with the aircraft's flight controls or engine, but the variable wind had changed directions during the descent from 1,000 feet agl, and the aircraft was therefore landing with a tailwind. In addition, the pilot states that the density altitude was approximately 5,700 feet, which left little room for error. In his discussion with the NTSB, the pilot stated that under the conditions, he should have initiated a go-around when he sensed the excessive descent rate at 100 feet agl.

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

The pilot's improper in-flight decision to continue a simulated engine-out autorotation after sensing an excessive descent rate at 100 feet above the ground. Factors include the excessive descent rate, variable winds, and a high density altitude.

Full narrative available

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