Probable cause
The partial loss of engine power during takeoff due to an oil pump/tachometer drive gear failure for undetermined reasons.
NTSB analysis
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.
Text from the NTSB. Open the NTSB docket for WPR09LA077 for the full record.
Event
- Date
- Jan 10, 2009
- Type
- Accident
- Place
- Fremont, California
- Nearest airport
- Palo Alto Airport Of Santa Cla (KPAO)
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Night
Cessna R172K
- N-number
- N758FN
- Category
- Airplane
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Personal
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.