LAX89LA273 · Cessna 172N
North Air Cessna 172N · Accident: partial loss of engine power (mechanical failure) en route
From Prescott Regional Airport - Ernest A. Love Field (PRC) to an unrecorded destination
Event
- NTSB case
- LAX89LA273
- 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
- 0
- 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 172N
- 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
- N5961J
- Operator
- North Air
- Onboard fatalities
- Unknown
- Route
- From Prescott Regional Airport - Ernest A. Love Field (PRC), Prescott, AZTo not recorded
- 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
- En route · cruise
- First occurrenceThe 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
- Partial loss of engine power (mechanical failure)
- 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
- Engine assembly, valve, exhaust › Failure, total
- Engine assembly, valve, exhaust › Jammed
- Terrain condition › Berm
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE PILOT REPORTED THAT WHILE IN CRUISE FLIGHT, A SEVERE VIBRATION BEGAN IN THE ENGINE WITH A CORRESPONDING REDUCTION IN ENGINE RPM TO ABOUT 1500. THE PILOT NOTED THAT ALL ATTEMPTS AT REMEDIAL ACTION MET WITH NO SUCCESS AND THE ENGINE WAS PRODUCING INSUFFICIENT POWER TO MAINTAIN FLIGHT. THE PILOT ATTEMPTED TO LAND ON AN INTERSTATE HIGHWAY BUT THERE WAS TOO MUCH VEHICLE TRAFFIC TO MAKE A SAFE LANDING. THE PILOT THEN LANDED IN A DIRT FIELD ADJACENT TO THE HIGHWAY, CONTACTED A LARGE BERM DURING THE LANDING ROLL OUT AND THE AIRCRAFT NOSED OVER ON ITS BACK. EXAMINATION OF THE ENGINE REVEALED HEAVY DEPOSITS ON THE INTAKE AND EXHAUST VALVES. THE EXHAUST VALVE FOR THE NUMBER 3 CYLINDER WAS IN THE CLOSED POSITION AND COULD NOT BE MOVED. DETAILED EXAMINATION OF THE NUMBER 3 CYLINDER REVEALED THAT THE ROCKER ARM PIVOT STUD FOR THE EXHAUST VALVE WAS BROKEN WITH SHEAR SIGNATURES EVIDENT.
Probable cause
A LOSS OF ENGINE POWER DUE TO A FAILURE OF THE NUMBER 3 CYLINDER EXHAUST VALVE ROCKER ARM PIVOT STUD, WHICH WAS IN TURN CAUSED BY A STUCK EXHAUST VALVE.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX89LA273
- Event ID
- 20001213X29158
- Case number
- LAX89LA273
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 9ed577673ac49e44253891aa37b1ade655d1378024e934e1835b71e32fe6b211; retrieved 2026-09-22T00:04:47.168Z.