Pilot Debrief

BEECH G35 near Surprise, AZ — 2016-05-07

Final reportWPR16FA102
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Date
2016-05-07
Location
Surprise, AZ, USA
Aircraft
BEECH G35
Registration
N4401D
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Climb

Probable cause

The mechanic's failure to properly secure the bolt connecting the throttle cable to the carburetor during the installation of the carburetor, which resulted in a loss of engine power.

NTSB narrative

The flight instructor was asked to complete a maintenance test flight of the airplane following the installation of a repaired carburetor. He elected to use the flight to provide instruction to the private pilot who had requested a checkout in the airplane. The private pilot reported that the flight was initially normal, but then the engine stopped responding to throttle control. According to the private pilot, the engine remained at idle power as the airplane descended and impacted trees in a residential area. Examination of the wreckage revealed that the carburetor throttle cable was detached from the throttle body linkage. The bolt and castellated nut used to secure the throttle cable to the linkage were found lying separately in the engine cowling; there was no evidence that a cotter pin had been used to secure the nut on the bolt, as required. It is likely that the loss of engine power resulted from the failure of the mechanic who installed the carburetor to install the cotter pin when he attached the throttle cable to the carburetor. During the maintenance test flight, the castellated nut backed off of the bolt, which resulted in a loss of throttle control.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Performing a thorough pre-flight inspection of the carburetor installation.

NTSB coding

Evidence available

  • Video
  • ADS-B / radar
  • Photos
  • 14 docket documents
View NTSB final reportView NTSB docket

Docket documents14

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