Pilot Debrief

GRUMMAN G164 near Tracy, CA — 2010-08-11

Final reportWPR10LA396
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Date
2010-08-11
Location
Tracy, CA, USA
Aircraft
GRUMMAN G164
Registration
N6781K
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Maneuvering

Probable cause

A total loss of engine power while maneuvering due to an internal catastrophic failure to the master rod and piston connecting rod links.

NTSB narrative

During an aerial application flight, the pilot heard a loud bang, which was followed by a loss of engine power and shaking. During the forced landing to a wet field, the pilot activated the left brake to intentionally ground-loop the airplane; however, it did not respond. The airplane continued its forward movement until it struck a fence at the end of the field and came to rest inverted. During the postaccident engine examination, it was discovered that the connecting links for all but the No. 7 cylinder were broken and the master rod was sheared. Due to the extent of internal damage, it could not be determined if the master rod or the connecting link had failed first.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have checked engine condition before flight to prevent power loss.

NTSB coding

Evidence available

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

Docket documents4

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