Pilot Debrief

ROBINSON HELICOPTER COMPANY R44 II near Ronan, MT — 2017-07-06

Final reportWPR17LA143
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Date
2017-07-06
Location
Ronan, MT, USA
Aircraft
ROBINSON HELICOPTER COMPANY R44 II
Registration
N442DR
Category
Helicopter
Highest injury
Serious
Fatalities
0
Phase of flight
Maneuvering

Probable cause

The pilot's failure to maintain adequate airspeed, which resulted in a loss of tail rotor effectiveness during a low-altitude orbiting maneuver and a subsequent hard landing.

NTSB narrative

The private pilot departed on a local, private flight in the helicopter with a family member onboard for a scenic tour of the area. The pilot reported that, about 45 minutes into the flight, he slowed the helicopter to 35 knots, descended it to about 300 ft above ground level (agl), and then entered a left orbiting turn to follow an animal. The helicopter then experienced an uncommanded yaw, which the pilot perceived as a loss of tail rotor authority, and it then began to spin clockwise and descend. The pilot immediately attempted to counteract the spin by lowering the collective control, reducing power, and applying left antitorque pedal, which he maintained for the rest of the descent. When the helicopter was about 5 ft agl, the pilot pulled the collective control, but he was unable to arrest the descent, likely because the descent rate was too high, and the helicopter subsequently impacted the ground hard, which resulted in substantial damage to the tail cone and tail rotor. Postaccident helicopter examination revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. Further, the pilot reported that there were no problems with the engine and that it continued to run normally after the helicopter came to rest. It is likely that the pilot allowed the airspeed to drop below translational lift, which resulted in a loss of tail rotor effectiveness and a subsequent spin. Despite remedial actions to compensate for the spin, the descent rate was likely too high to arrest it, which resulted in the hard landing.

Analysis

Primary failure mode
Loss of control
First missed decision gate
Pilot could have maintained airspeed to prevent loss of tail rotor authority.

NTSB coding

Evidence available

  • Photos
  • 11 docket documents
View NTSB final reportView NTSB docket

Docket documents11

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