LAX92LA276 · Cessna 421B
Cessna 421B · Accident: explosion while standing
From Hayward Executive Airport (HWD) to Oakland San Francisco Bay Airport (OAK)
Event
- NTSB case
- LAX92LA276
- 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 421B
- Aircraft type
- Cessna 421
- 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
- N11BU
- Operator
- Professional Pilot Associates
- Onboard fatalities
- Unknown
- Route
- From Hayward Executive Airport (HWD)To Oakland San Francisco Bay Airport (OAK), Oakland, 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
- Standing · engine(s) start-up
- 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
- Explosion
- 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 › Leak
- Pilot in command › Mixture, excessive
- Pilot in command › Starting procedure, improper use of
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE PILOT REPORTED THAT HE OVERPRIMED THE RIGHT ENGINE WHEN HE ATTEMPTED TO START IT. DURING THE START OPERATION, AN ACCUMULATION OF FUEL VAPOR LOCATED OUTBOARD OF THE RIGHT ENGINE EXPLODED AND RIPPED OPEN A YARD LONG PORTION OF THE RIGHT WING'S UPPER SKIN PANELS. EVIDENCE WAS OBSERVED OF AN UNCORRECTED PREEXISTING FUEL LEAK IN THE VICINITY OF THE RIGHT ENGINE'S AUXILIARY FUEL PUMP. THE PILOT REPORTED THAT HE WAS AN A & P MECHANIC, AND HE OWNED, OPERATED AND MAINTAINED THE AIRPLANE.
Probable cause
THE EXPLOSION OF FUEL VAPORS IN THE RIGHT WING DUE TO THE PILOT'S OVERPRIMING OF THE RIGHT ENGINE DURING A START ATTEMPT AND AN UNCORRECTED PREEXISTING FUEL SYSTEM LEAK. A FACTOR IN THE ACCIDENT WAS INADEQUATE MAINTENANCE PERFORMED ON THE AIRCRAFT.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX92LA276
- Event ID
- 20001211X15178
- Case number
- LAX92LA276
- 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. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1992-07-03.
- API snapshot SHA-256: bebdab7cbeb262365055235fe212d64c653f812b257a294b5263fb89b8226999; retrieved 2026-09-23T02:59:11.549Z.