NTSB Identification: DEN02LA019.
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Accident occurred Friday, January 11, 2002 in Aurora, CO
Probable Cause Approval Date: 12/06/2002
Aircraft: McDonnell Douglas MD 902, registration: N902AM
Injuries: 3 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.
An instructor pilot was conducting transition training and was demonstrating emergency procedures on anti-torque malfunctions and loss of thrust/fixed pedal settings. After reaching a final approach position at approximately 100 feet agl, he began to demonstrate how to complete an approach with an "Anti-Torque Failure - Fixed Thruster Setting." He established the helicopter on a "shallow" approach angle with a deceleration attitude of approximately 15 to 20 degrees nose up and approximately 300 feet per minute rate of descent. The flight profile "appeared normal" until about 50 to 60 feet above ground level when the helicopter started to descend at a higher than desired rate for demonstration. The pilot applied collective lever control and a shudder was felt in the rotor system, followed by an increase in descent rate. Collective lever application could not arrest the descent. The helicopter struck the ground hard in a nose high attitude, ballooned into the air approximately 3 to 5 feet and slowly rotated approximately 360 degrees. The "thruster" was jammed in the neutral position, but he had no problem landing the helicopter from a hover with power. The helicopter sustained substantial damage to the Notar Anti-Torque rotating thruster cone, the aft cross tube, and both landing gear skids.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: the pilot's failure to maintain aircraft control due to inadvertent settling with power resulting in a hard landing. Contributing factors include the improperly planned approach, the high density altitude, and the encounter with vortex ring state. Full narrative available
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