Pilot Debrief

WESTERN INTERNATIONAL AVIA INC UH 1H near Arbuckle, CA — 2017-10-13

Final reportWPR18LA004
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Date
2017-10-13
Location
Arbuckle, CA, USA
Aircraft
WESTERN INTERNATIONAL AVIA INC UH 1H
Registration
N247PV
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

A collective control malfunction for reasons that could not be determined.

NTSB narrative

The pilot and mechanic reported that, before the accident, the mechanic had adjusted the helicopter’s main rotor track and balance. After the mechanic made the final adjustments, the pilot hovered the helicopter to a wash rack for cleaning. Subsequently, while the pilot was repositioning the helicopter to a nearby landing cart and just as the front portions of the skids were over the cart, the collective began to oscillate, followed by the skids striking the cart. The pilot attempted to land the helicopter as it continued to oscillate, but the right skid slid off the cart. The helicopter then rolled onto its right side and impacted the ground. The mechanic reported that all components prior to the accident were in good working order and that the track and balance adjustments had resulted in satisfactory monitoring equipment readings prior to the accident. Examination of the helicopter did not reveal evidence of any preaccident malfunctions or failures that would have precluded normal operation. The reason for the oscillations could not be determined based on the available information.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted the maneuver when collective surged uncommanded.

NTSB coding

Evidence available

  • 2 docket documents
View NTSB final reportView NTSB docket

Docket documents2

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