Pilot Debrief

BELL 47G 5 near San Ardo, CA — 2016-04-29

Final reportWPR16LA099
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Date
2016-04-29
Location
San Ardo, CA, USA
Aircraft
BELL 47G 5
Registration
N6288N
Category
Helicopter
Highest injury
Minor
Fatalities
0
Phase of flight
Descent

Probable cause

The failure of the pin in the outboard end of the lateral flight control torque tube.

NTSB narrative

While performing an agricultural flight, the pilot of the helicopter heard a loud noise followed by a vibration in the flight controls, and the helicopter began to roll. He noted that the cyclic was stiffer than normal, and his control inputs produced a delayed response from the helicopter. The pilot was able to return the helicopter to level flight and attempted a run-on landing; however, the helicopter began a roll to the left, which he was not able to correct before the main rotor blades impacted the ground and the helicopter rolled onto its side, resulting in substantial damage. Postaccident examination revealed that the pin for the outboard end torque tube, which controlled lateral movement of the swashplate, was fractured.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted the spray pass after hearing the loud noise.

NTSB coding

Evidence available

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

Docket documents3

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