Cessna 421B accident near Hayward, California, July 3, 1992
On July 3, 1992, a Cessna 421B, registered N11BU, was substantially damaged in an accident near Hayward, California (Hayward airport). It was a positioning flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 3, 1992
- Place
- Hayward, California · Hayward · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 421B · all 421Bs on the register
- Registration
- N11BU · no longer on the register · serial 421B0912
- Damage
- Substantial damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 7,900 hours in all; 900 in this make and model; 80 in the last 90 days; 22 in the last 30 days; 7,800 as pilot in command
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Last inspection: 100-hour inspection, April 8, 1992; 90 hours since
- Maximum gross weight: 7,450 lb
- Seats: 8
- Landing gear: retractable
- Engine: Continental GTSIO-520H (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: HWD
- Destination: OAK Oakland CA
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 270° at 5 knots
- Sky: clear
- Temperature: 70°F (21°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.