ANC03LA083

NTSB accident investigation · Maule M-4 · Kobuk, AK · July 20, 2003

Accident · Minor injuriesLimited investigationFinal report
Date
July 20, 2003, 12:45 local (20:45 UTC)
Place
Kobuk, AK
Injuries
1 minor
Damage
Substantial damage
Phase of flight
Initial climb
Aircraft
N40344Maule M-4
Weather
Visual (VMC) · Day
Status
Completed · report February 5, 2004
Report
Approved by Office Director
NTSB office
Alaska Regional Office
Parties
FAA-AL-FAI FSDO 01
FAA report
20030720036259A
Case key
57545

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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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

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine power(partial) - nonmechanicalTakeoff - initial climb
Fuel supply - inadvertent usePilot in commandCause
Fluid,fuel - contamination,other than waterCause
Aircraft preflight - inadequatePilot in commandFactor
Forced landingEmergency landing after takeoff
In flight collision with objectEmergency 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
Reported as
Maule M-4
Category
Airplane
Serial number
2120C
Airframe hours
1,742
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
56
Injuries
Minor
Certificate
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.