Pilot Debrief

CESSNA T188C near Montezuma, IN — 2010-07-29

Final reportCEN10LA450
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Date
2010-07-29
Location
Montezuma, IN, USA
Aircraft
CESSNA T188C
Registration
N2085J
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The total loss of engine power due to an insufficient fastener preload that led to the failure of the No. 2 connecting rod assembly.

NTSB narrative

The pilot reported that, while en route to spray a field, the engine lost power and the windshield became obscured with oil. The pilot immediately turned into the wind and made a forced landing into a nearby cornfield. A postaccident examination revealed that the No. 2 connecting rod had separated from the engine crankshaft. Metallurgical examinations found polishing and wear patterns indicative of relative motion between the connecting rod components and an associated rod bolt head/nut. The nut threads were sheared as result of overload failure, consistent with impulse loading. The observed anomalies were consistent with an insufficient fastener preload on installation of the connecting rod bolt. The engine had accumulated 1,193 hours since its last major overhaul. It is likely that the rod bolt head/nut became loose during operation, which led to a failure of the assembly due to impulse loading.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have conducted a thorough preflight inspection to identify engine issues.

NTSB coding

Evidence available

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

Docket documents6

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