Pilot Debrief

North American SNJ near Agoura Hills, CA — 2018-10-23

Final reportWPR19LA014
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Date
2018-10-23
Location
Agoura Hills, CA, USA
Aircraft
North American SNJ
Registration
N7969C
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Initial climb

Probable cause

The failure of the No. 5 piston rod end due to fatigue, which resulted in a total loss of engine power.

NTSB narrative

The pilot reported that, shortly after departure, he heard two loud bangs followed by total loss of engine power. The pilot performed a forced landing to a highway, during which the airplane swerved to the left, the left wing impacted a concrete center divider, and a postimpact fire ensued. Initial examination of the engine found that the No. 2 cylinder was cracked, and the No. 1 cylinder and the base between the Nos. 4 and 5 cylinders displayed damage. Disassembly of the engine revealed the piston-end master rod piece from the No. 5 cylinder fractured through the I-beam shaft. Microscopic examination of the fracture surface showed evidence of fatigue. The initiation point of the fatigue fracture was damaged due to mechanical contact during the failure sequence. The accident is consistent with a total loss of engine power following the failure of the No. 5 master rod end. The initiating point and cause of the fatigue failure could not be identified based on the available evidence.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted takeoff after hearing loud bangs.

NTSB coding

Evidence available

  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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