Pilot Debrief

Grumman G164 near Opelousas, LA — 2018-08-29

Final reportCEN18LA357
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Date
2018-08-29
Location
Opelousas, LA, USA
Aircraft
Grumman G164
Registration
N956X
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

The loss of two securing bolts that allowed the left magneto to move around, which disrupted the spark timing and resulted in the engine losing total power.

NTSB narrative

The private pilot was practicing crop-dusting maneuvers when the engine lost total power; he performed a forced landing in an open, muddy field. The airplane nosed over and sustained substantial damage. Postaccident examination of the engine revealed that two of three bolts that secured the left magneto had come loose and were missing. The safety wire was broken, and the Sims coupling was heavily damaged. The magneto could easily be moved around, which disrupted the spark timing and resulted in a total loss of power.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Ensure all engine components are secure before flight to prevent power loss.

NTSB coding

Evidence available

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

Docket documents3

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