Pilot Debrief

BEECH 35-C33 near St. George, UT — 2012-03-21

Final reportWPR12LA147
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Date
2012-03-21
Location
St. George, UT, USA
Aircraft
BEECH 35-C33
Registration
N866P
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The total loss of engine power due to the loose mixture control arm.

NTSB narrative

The pilot reported that, while in cruise flight, the engine’s exhaust gas temperature was hotter than normal and that the fuel flow was lower than normal. Suddenly, all engine power was lost and despite multiple attempts, he was unable to restart the engine. During the subsequent forced landing, the pilot landed the airplane gear up on a road. Postaccident examination of the engine revealed that the mixture control arm was loose on the control shaft and the nut that secured the control arm to the shaft was loose. The mixture control arm machined chamfer had formed splines and exhibited deformation and movement of material. The nut and control arm mating surfaces showed corresponding rub marks. It is likely that the loose mixture control arm and the vibration of the engine allowed for the mixture control shaft to rotate to an idle cut-off position, thus resulting in the loss of engine power. No evidence of any additional mechanical malfunctions was found during the engine examination.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have conducted a precautionary landing upon noticing engine anomalies.

NTSB coding

Evidence available

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

Docket documents4

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