Pilot Debrief

Cessna 177 near Lodi, CA — 2020-04-29

Final reportWPR20LA133
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Date
2020-04-29
Location
Lodi, CA, USA
Aircraft
Cessna 177
Registration
N3386T
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Climb

Probable cause

The fatigue failure of the no. 4 cylinder connecting rod, which resulted in a total loss of engine power.

NTSB narrative

The student pilot reported that about 15 minutes after takeoff, he heard a loud noise and observed oil on the windscreen, followed by a total loss of engine power. The pilot attempted to restart the engine but was unsuccessful and initiated a forced landing to a nearby field. Subsequently, the airplane landed hard and came to rest upright, which resulted in substantial damage to the fuselage. Postaccident examination of the engine revealed that the No. 4 connecting rod had failed. Metallurgical examination of the connecting rod revealed that it had fractured from a fatigue crack, which initiated at an inner flange corner of the rod, about 1.15 inches from the piston pin bore. Once the connecting rod was no longer connected, the lower portion of the connecting rod (closer to the crankshaft) fractured in bending overstress, beginning a cascade of wider damage while the reciprocating engine was running.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have performed a precautionary landing after engine began to run rough.

NTSB coding

Evidence available

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

Docket documents6

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