WPR09LA077 · Cessna R172K
Cessna R172K · Accident: loss of engine power (partial) during initial climb
From Palo Alto Airport (KPAO) to Palo Alto Airport (KPAO)
Event
- NTSB case
- WPR09LA077
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Cessna R172K
- Aircraft type
- Cessna 172
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N758FN
- Operator
- Bronson Mark W
- Onboard fatalities
- Unknown
- Route
- From Palo Alto Airport (KPAO), Palo Alto, CATo Palo Alto Airport (KPAO), Palo Alto, CA
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Initial climb
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of engine power (partial)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft power plant
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
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.
Probable cause
The partial loss of engine power during takeoff due to an oil pump/tachometer drive gear failure for undetermined reasons.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR09LA077
- Event ID
- 20090110X53455
- Case number
- WPR09LA077
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2009-01-10.
- API snapshot SHA-256: 9727868a005459e06796734d324891fec2f193ab945038c38fc02321415d198d; retrieved 2026-09-15T10:40:45.725Z.