Cessna 421C accident near Lancaster, California, July 18, 1990
On July 18, 1990 at about 4:33 pm local time, a Cessna 421C, registered N6089X, was substantially damaged in an accident near Lancaster, California (Gen. William J Fox airport). It was a business flight under general aviation rules (Part 91). No one was hurt; 5 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE ACCIDENT WAS ERODED IGNITION SPARK PLUG ELECTRODES AND MAINTENANCE PERSONNEL NEGLECTING TO ADJUST SPARK PLUG ELECTRODES AND MAINTENANCE PERSONNEL NEGLECTING TO ADJUST SPARK PLUG GAP. THE ROUGH TERRAIN IN WHICH THE AIRCRAFT LANDED WAS A FACTOR IN THE ACCIDENT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 18, 1990 · about 4:33 pm local time
- Place
- Lancaster, California · Gen. William J Fox · map
- Type
- Accident
- Injuries
- No one was hurt; 5 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 421C · all 421Cs on the register
- Registration
- N6089X · registry record · serial 421C0887
- Damage
- Substantial damage
- Flight
- Business flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
ERODED IGNITION SPARK PLUG ELECTRODES AND MAINTENANCE PERSONNEL NEGLECTING TO ADJUST SPARK PLUG ELECTRODES AND MAINTENANCE PERSONNEL NEGLECTING TO ADJUST SPARK PLUG GAP. THE ROUGH TERRAIN IN WHICH THE AIRCRAFT LANDED WAS A FACTOR IN THE ACCIDENT.
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: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 59,000 hours in all; 402 in this make and model; 270 in the last 90 days; 90 in the last 30 days; 42,000 as pilot in command; 40,000 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded; 0 hours since
- Maximum gross weight: 7,450 lb
- Seats: 8
- Landing gear: retractable
- Engine: Continental GTSI-O-520-L (piston); 0 hours total
- Operator: Pacifica Corporation
The flight
- Departed from: WJF at 4:30 pm
- Destination: APV Apple Valley CA
- Flight plan: none
- Runway 24, 5,001 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 240° at 5 knots
- Visibility: 40 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
- Observation at 4:30 pm from WJF, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 4 |
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.