Pilot Debrief

CESSNA R172K near Fremont, CA — 2009-01-10

Final reportWPR09LA077
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Date
2009-01-10
Location
Fremont, CA, USA
Airport
KPAO
Aircraft
CESSNA R172K
Registration
N758FN
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Initial climb

Probable cause

The partial loss of engine power during takeoff due to an oil pump/tachometer drive gear failure for undetermined reasons.

NTSB narrative

The pilot reported that after takeoff, and during a left turn, he heard a sudden change in the engine sound followed by a loss of power. He stated that he increased and decreased the throttle with little response from the engine and elected to make a precautionary landing onto a nearby levy. During the landing roll on the levy, the airplane veered to the right, exited the levy, and nosed over in a bog. Both wings sustained substantial damage. Examination of the engine revealed that the oil pump/tachometer drive gear separated from the base of its driveshaft. Metallurgical examination revealed that the oil pump drive gear failed at the intersection of the shaft and gear. Scanning electron microscope images of the fracture showed raised and flattened areas typical of contact damage during cyclic loading. The cause of the fracture was not determined.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted the flight after noticing low oil temperature.

NTSB coding

Evidence available

  • 4 docket documents
View NTSB final reportView NTSB docket

Docket documents4

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