Pilot Debrief

AIRBUS AS-350 near Hamilton, MT — 2015-05-04

Final reportANC15LA076
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Date
2015-05-04
Location
Hamilton, MT, USA
Airport
6S5
Aircraft
AIRBUS AS-350
Registration
N504WD
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Hover

Probable cause

The pilot's excessive collective application during an autorotation. Contributing to the accident was the flight instructor's inadequate supervision of the training flight.

NTSB narrative

The flight instructor, in the left seat reported that he was providing flight instruction to the commercial pilot, in the right seat, which included a series of hovering autorotations. According to the instructor, as the commercial pilot hovered the helicopter about 3 or 4 ft above the ground, the instructor initiated the hovering autorotation by reducing the floor-mounted throttle (fuel flow control lever) to about 70% N1, and the helicopter descended to about 1 ft above the ground. As the commercial pilot tried to cushion the touchdown, he inadvertently applied too much collective pitch, and the helicopter ballooned to a higher altitude. During the second descent, the main rotor rpm continued to decay, and the helicopter’s skids struck the ground. The instructor did not take control of the helicopter during this sequence. A postflight inspection revealed substantial damage to the tailboom.

Analysis

Primary failure mode
Human factors
First missed decision gate
Instructor could have ensured better throttle control before initiating autorotation.

NTSB coding

Evidence available

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

Docket documents14

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