# NTSB ANC03LA083: Maule M-4, N40344, Kobuk, AK, July 20, 2003 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 20, 2003, 12:45 local (20:45 UTC) - Place: Kobuk, AK - Coordinates: 66.943336, -156.904724 - Nearby events: https://openairdocs.org/map.md?lat=66.9433&lon=-156.9047&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report February 5, 2004 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-AL-FAI FSDO 01 - NTSB case key (mKey): 57545 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC03LA083 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/57545/pdf - Page: https://openairdocs.org/ntsb/ANC03LA083 ## Probable cause 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. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - nonmechanical, takeoff - initial climb - fuel supply - inadvertent use, pilot in command (cause) - fluid,fuel - contamination,other than water (cause) - aircraft preflight - inadequate, pilot in command (contributing factor) - Forced landing, emergency landing after takeoff - In flight collision with object, emergency landing after takeoff - object - tree(s) ## Analysis 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. ## Factual narrative On July 20, 2003, about 1245 Alaska daylight time, a tundra tire-equipped Maule M-4 airplane, N40344, sustained substantial damage when it collided with trees during a forced landing following takeoff from the Dahl Creek Airport, about 1.5 miles northwest of Kobuk, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, the sole occupant, received minor injuries. Visual meteorological conditions prevailed. The planned destination was Fairbanks, Alaska. No flight plan was filed, nor was one required. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on July 22, the pilot reported that after liftoff from runway 26 at Dahl Creek, the engine power began to decrease slowly. He 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 said he 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. Runway 26 at Dahl Creek has a gravel surface that is 4,780 feet long and 75 feet wide. The pilot said the sky condition was clear, the wind was from the southwest about 10 knots, and the temperature was about 70 degrees F. In the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the pilot, the pilot indicated that prior to the accident flight, he fueled the airplane with 14 gallons of fuel from a 55 gallon drum that he has 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. On October 9, in a telephone conversation with the NTSB IIC, the pilot reported that following the accident, he 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. ## Aircraft - Registration: [N40344](https://openairdocs.org/aircraft/N40344), registered now, S/N 2120C, built 1972 (OpenAirDocs) - Reported make and model: Maule M-4 - Registry model: [Maule M-4-220C](https://openairdocs.org/model/maule-m-4-220c) (registry code 5460114) (OpenAirDocs) - Registry engine: [Franklin 6A-350SER](https://openairdocs.org/engine/franklin-6a-350ser) (registry code 27023, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2120C - Airframe hours: 1742 - Engines: FRANKLIN GA-350-C1 220 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Max C. Lyon Jr. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 3, 2003, 17 hours before - Departed: DCK, KOBUK, AK - Destination: PAFA, FAIRBANKS, AK - Airport: DCK, Dahl Creek, runway 26, 4,780 × 75 ft, gravel ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: minor; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, valid medical--w/ waivers/lim; last flight review August 5, 2001; seat: left; flight hours: 1,063 total, 586 in this make and model, 1,063 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 225° at 10 knots - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 70 °F ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20030720036259A](https://openairdocs.org/incident/20030720036259A), Jul 20, 2003: Maule M4220C, Kobuk, AK, Substantial damage. (-23) [privacy data omitted] pilot stated that after takeoff from runway 26 at dahl creek, Alaska his aircraft engine gradually lost power. He made an attempt… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.