Maule M-4-220C accident near Byron, California, June 2, 1991
On June 2, 1991 at about 6:04 pm local time, a Maule M-4-220C, registered N40693, was substantially damaged in an accident near Byron, California (Byron Aprt airport). It was a personal flight under general aviation rules (Part 91). 2 people had minor injuries; 1 other was unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE FAILURE OF THE PILOT-IN-COMMAND TO PERFORM AN ADEQUATE PREFLIGHT INSPECTION BY TAKING THE NECESSARY STEPS TO ELIMINATE WATER CONTAMINATION OF THE AIRPLANE'S FUEL SYSTEM.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 2, 1991 · about 6:04 pm local time
- Place
- Byron, California · Byron Aprt · map
- Type
- Accident
- Injuries
- 2 people had minor injuries; 1 other was unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Maule M-4-220C · all M-4-220Cs on the register
- Registration
- N40693 · no longer on the register · serial 2183C
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
A MAULE M-4-220C COLLIDED WITH A FOUR FOOT HIGH DIRT BANK AFTER A LOSS OF ENGINE POWER DURING TAKEOFF. THE PILOT REPORTED THE ENGINE POWER WAS SURGING DURING THE INITIAL TAKEOFF CLIMB. AT 75 FT AGL THE ENGINE STOPPED. THE ENGINE STARTED AND RAN WITHOUT ANY MALFUNCTIONS DURING A POST ACCIDENT EXAM. THE PILOT SUSPECTED POSSIBLE WATER IN THE FUEL OR SEDIMENTS TEMPORARILY BLOCKING A FUEL LINE. THE AIRPLANE WAS LAST FLOWN 1 WEEK EARLIER FOR 1 HR AND 15 MIN. FUELING RECORDS ESTABLISHED THAT THE AIRPLANE WAS FUELED WITH 8.9 GALLONS OF AVIATION FUEL AFTER THE FLIGHT. THE FUEL CONSUMPTION FOR THE ENGINE AVERAGES IN EXCESS OF 12 GAL/HR. THE FAA RECOMMENDS THAT THE FUEL TANKS BE COMPLETELY FILLED AFTER EACH FLIGHT, OR AT LEAST AFTER THE LAST FLIGHT OF THE DAY. THE REASON IS THAT WHEN AIR IN THE FUEL TANK COOLS, THE MOISTURE IT CONTAINS CONDENSES INTO WATER, AND CONTAMINATES THE FUEL. PILOTS SHOULD TAKE THE NECESSARY STEPS TO ELIMINATE IT DURING PREFLIGHT INSPECTION.
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: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 1,362 hours in all; 125 in this make and model; 24 in the last 90 days; 12 in the last 30 days; 1,039 as pilot in command; 495 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 862 hours
- Last inspection: annual inspection, May 18, 1991; 2 hours since
- Maximum gross weight: 2,300 lb
- Seats: 4
- Landing gear: fixed
- Engine: Franklin 6A-350-C1 (piston); 0 hours total
The flight
- Destination: SQL San Carlos CA
- Flight plan: none
- Runway 22, 2,800 ft by 30 ft
Weather at the time
- Light: daylight
- Wind: from 290° at 14 knots
- Visibility: 30 statute miles
- Sky: scat
- Temperature: 64°F (18°C), dew point 52°F (11°C)
- Altimeter: 29.00 inHg
- Observation at 5:45 pm from CCR, 24 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 | 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.