Pilot Debrief

CESSNA 120 near Gonzales, LA — 2015-11-06

Final reportCEN16LA033
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Date
2015-11-06
Location
Gonzales, LA, USA
Airport
L38
Aircraft
CESSNA 120
Registration
N2942N
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Approach

Probable cause

Maintenance personnel’s improper installation of the carburetor during recent maintenance, including the omission of a required cotter pin, which resulted in a total loss of engine power.

NTSB narrative

The pilot reported that the airplane was on final approach to the airport when the engine started to lose power. He applied carburetor heat and switched fuel tanks, but engine power was not restored, so he made a forced landing to a field near the airport. An examination of the wreckage found that the castellated nut that connects the throttle arm to the carburetor had backed off, which allowed the engine to go to idle, and that the nut's associated cotter pin was missing. The pilot reported that the carburetor had been replaced the day before the accident flight. The accident is consistent with the throttle arm becoming disengaged from the carburetor as a result of a missing cotter pin and the accompanying nut subsequently backing off.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have checked carburetor installation before flight.

NTSB coding

Evidence available

  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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