Pilot Debrief

HUGHES 269C near Darrington, WA — 2014-08-11

Final reportWPR14LA340
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Date
2014-08-11
Location
Darrington, WA, USA
Aircraft
HUGHES 269C
Registration
N7432F
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Descent

Probable cause

Maintenance personnel’s failure to secure the throttle mount bracket during a recent engine installation, which resulted in the loss of throttle movement and an inability to control engine power.

NTSB narrative

The commercial pilot was conducting a local, personal flight in the rented helicopter. The pilot reported that, while descending the helicopter from 5,000 ft and approaching 4,000 ft, he increased the collective and noticed that the engine was slowing down; he was unable to recover the engine rpm to a normal range. The helicopter continued to descend until the pilot entered an autorotation. The helicopter then impacted a tree and came to rest in a small stream. The pilot stated that he did not believe that the engine ever quit but that it did not produce enough power to continue flight. Postaccident examination of the helicopter revealed that the throttle mount bracket was hanging by the throttle cable linkage and was not secured to the servo mount studs, which would have led to the loss of throttle movement for acceleration. The operator stated that the engine had been installed in the helicopter 10 flight hours before the accident. It is likely that maintenance personnel did not properly secure the throttle mount bracket during the engine installation, which led to the loss of throttle movement and inability to control engine power.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have aborted the flight after noticing engine power issues.

NTSB coding

Evidence available

  • 2 docket documents
View NTSB final reportView NTSB docket

Docket documents2

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