LAX01FA271 · Cessna 336
Cessna 336 · Accident: partial loss of engine power (non-mechanical) en route
From General William J Fox Airfield (WJF) to San Gabriel Valley Airport (EMT)
Event
- NTSB case
- LAX01FA271
- 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 336
- Aircraft type
- Cessna 336
- 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
- N3838U
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From General William J Fox Airfield (WJF), Lancaster, CATo San Gabriel Valley Airport (EMT), El Monte, 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
- 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 (non-mechanical)
- 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
- Fuel system, primer system › Excessive flow/output
- Fuel system, primer system › Unlocked
- Ignition system, spark plug › Fouled
- Pilot in command › Aircraft preflight, inadequate
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The airplane experienced a loss of engine power in the aft engine and collided with a guardrail during an off-airport emergency landing on a highway. The pilot flew the airplane earlier that afternoon with no mechanical discrepancies noted. After takeoff and leveling off at 4,500 feet, the pilot thought he noticed a loss of engine power in both engines because he was unable to maintain altitude. A forced landing was performed on a highway and the airplane went through a guardrail. A post accident examination revealed the primers were left unlocked with the aft engine primer pulled out approximately 1 inch. Black sooty deposits were discovered on the rear engine spark plugs. The primer is as an optional feature to assist in cold weather operations.
Probable cause
The pilot's inadequate preflight inspection of the primer controls, resulting in excessive fuel flow, spark plug fouling, and loss of engine power in the aft engine.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX01FA271
- Event ID
- 20010818X01724
- Case number
- LAX01FA271
- 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: 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 2001-08-06.
- API snapshot SHA-256: 61ce8c863b325c6ffdc2ed7140b6ba2035569f4e882877a72aa074baada4da65; retrieved 2026-09-21T09:55:48.827Z.