Maule M-4 accident near Kobuk, Alaska, July 20, 2003
On July 20, 2003 at about 8:45 pm local time, a Maule M-4, registered N40344, was substantially damaged in an accident near Kobuk, Alaska (Dahl Creek airport). It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's inadvertent use of diesel fuel in a gasoline engine which resulted in a partial loss of engine power, and subsequent collision with trees during a forced landing after takeoff. A factor contributing to the accident was the pilot's inadequate preflight inspection of the airplane that failed to detect the presence of diesel fuel in the fuel supply.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 20, 2003 · about 8:45 pm local time
- Place
- Kobuk, Alaska · Dahl Creek · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Maule M-4 · all M-4s on the register
- Registration
- N40344 · registry record · serial 2120C
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Prior to departure on the accident flight, the private certificated pilot fueled the airplane with 14 gallons of fuel from a 55 gallon drum that he stored at his cabin. He conducted a preflight of the airplane, which included draining the airplane's fuel sumps, and found no water in the sumps. After liftoff, the engine power began to decrease slowly. The pilot said the engine did not have any roughness or unusual sounds, but the rpm decreased to about 2,200 and the airplane began to lose altitude. About 200 feet above the ground, the pilot began to turn to the north in an effort to return to the runway, but the airspeed was decreasing. The airplane collided with numerous trees and sustained damage to the wings, lift struts, elevator, and the right main landing gear. Following the accident, the pilot examined the fuel from the airplane. He said he discovered that the fuel he placed in the airplane before departure was diesel fuel. He reported that his storage drum was mislabeled.
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: private
- Ratings: single-engine land; single-engine sea
- Flight time: 1,063 hours in all; 586 in this make and model; 1,063 as pilot in command
- Last flight review: August 5, 2001
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 1,742 hours
- Last inspection: annual inspection, March 3, 2003; 17 hours since
- Maximum gross weight: 2,300 lb
- Seats: 4
- Landing gear: fixed
- Engine: Franklin GA-350-C1 (piston); 0 hours total
The flight
- Departed from: DCK Kobuk AK at 3:45 pm
- Destination: PAFA Fairbanks AK
- Flight plan: none
- Runway 26, 4,780 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 225° at 10 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 70°F (21°C), dew point 0°F (-18°C)
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.