CEN13FA172

The pilot’s failure to transfer fuel from the auxiliary fuel tanks to the main fuel tanks in a timely manner, which resulted in fuel starvation to the engine.

The pilot was returning home from a cross-country business trip when the accident occurred. A witness reported hearing a "loud pop" that sounded like an "engine backfiring" followed by the sound of impact. Another witness reported seeing the airplane flying low and hearing the engine sputter just before the airplane impacted terrain. The airplane impacted a snow-covered field and traveled about 300 ft before it came to rest. First responders reported smelling fuel near the main wreckage. A postaccident examination of the airplane and engine did not reveal any mechanical anomalies that would have resulted in the accident. The airplane's fuel tanks were filled before departure. Each main fuel tank held 20 gallons of usable fuel, and each auxiliary fuel tank held 15 gallons of fuel. The main fuel tanks supplied fuel to the engine. The fuel selector was found in the "both" position. The auxiliary fuel tanks replenished the main fuel tanks via transfer pumps that were turned on by switches in the cockpit when needed; the fuel transfer pump switches were not located in the wreckage. The airplane's estimated fuel consumption rate was about 9 gallons per hour. According to the tachometer, the flight was 4.1 hours long, which would have used about 37 gallons of fuel plus additional fuel for taxi and climb. Thus, it is likely that the pilot did not transfer fuel from the auxiliary fuel tanks to the main fuel tanks in a timely manner, which resulted in the engine being starved of available fuel.

There were no known air traffic control communications with the airplane during the en route portion of the flight. Each main fuel tank held 20 gallons of usable fuel and each auxiliary tank held 15 gallons of fuel. The main fuel tanks supplied fuel to the engine. The auxiliary (outboard) tanks replenish the main fuel tanks via transfer pumps which are turned on by switches when needed. According to the pilot's brother, they had calculated that the engine fuel consumption averaged 9 gallons per hour. Their normal procedure for fuel management was to use the main fuel tanks until they were ½ full. They would then turn on the fuel pumps to replenish the main tanks from the auxiliary tanks. The pilot's brother stated the fuel transfer rate from the auxiliary tanks to the main tanks was very slow and that it would barely be enough to keep the engine running. Based on the tachometer time recorded on the paperwork provided by the FBO and the tachometer time at the accident site, the flight was 4.1 hours long. The pilot's iPhone 3GS was recovered from the accident site and sent to the NTSB Recorder Laboratory for examination. No Global Positioning System historical information was discovered on the phone; however, there was evidence that the pilot used an aviation application, ForeFlight (version 4.7.2) during the flight. Two ForeFlight flight plans correlating to the accident flight were discovered. One flight was direct from PIA to the "Menze-Aaron" private airport, with a calculated distance of 430 nautical miles. The other was from PIA to the Wadena Municipal Airport (ADC), Wadena, Minnesota, which had a calculated distance of 422 nautical miles. The ForeFlight screen for the flight from PIA to the Menze-Aaron private airport showed a course of 327 degrees magnetic, a planned fuel burn of 35.9 gallons, total time en route of 3 hours 35 minutes, and a message "Winds aloft not included." The pilot's brother stated that he experienced the engine backfiring once when he was flying. He stated the throttle was retarded for landing and the engine backfired when he advanced the throttle. An autopsy was performed on the pilot at the Lake Region Healthcare facility in Fergus Falls, Minnesota. The cause of death was attributed to trauma sustained from the aircraft accident. Toxicology testing was performed by the Federal Aviation Administration Civil Aerospace Medical Institute. Testing results were negative for all substances in the screening profile. Weather conditions recorded by the Automated Surface Observing Systems (ASOS), located at the Chandler Field Airport (AXN), Alexandria, Minnesota, 27 miles south of the accident site were: At 1753: wind 100 degrees at 5 knots, visibility 10 miles, clear sky conditions, temperature minus 13 degrees Celsius, dew point minus 19 degrees Celsius, and altimeter 30.35 inches of mercury. The accident airplane was a 1993 Maule MXT-7-180, serial number 14026C. It was a high wing, single-engine airplane, with fixed tricycle landing gear. The airplane was powered by a 180-horsepower Lycoming O-360-C1F reciprocating engine, serial number L-33266-36A. The airplane was issued a normal category airworthiness certificate on January 21, 1993. The pilot and his brother were co-owners of the airplane which they purchased on August 23, 2012. The aircraft and engine logbooks showed that the last annual inspections were performed on October 18, 2012, at a tachometer time of 1,349.6 hours, and a Hobbs meter time of 1,496.8 hours. In order to accommodate the pilot's medical condition, the throttle control was modified and the flap handle was extended. Logbook records show a new throttle friction lock was installed on August 30, 2012, and an EZ Flap extension, Supplemental Type Certificate SA02246LA, was installed on September 7, 2012. According to records obtained from a fixed base operator (FBO) at PIA, the pilot requested the airplane be "topped off" and the airplane was fueled with 34 gallons of 100LL aviation fuel. FBO personnel reported that prior to departing PIA, the pilot preheated the engine and then flooded the engine during the attempted start up. They put the airplane in a hangar, removed, cleaned, and checked the spark plugs, checked the mag timing, and charged the battery. No anomalies were noted so they closed the cowling and the pilot was able to start the engine. The tachometer reading was noted as 1,376.1 on the invoice. The tachometer reading at the time of the accident was 1,380.2. The pilot, age 41, held a private pilot certificate with a single engine land airplane rating. He was issued a third class airman medical certificate on September 3, 2009. The pilot held a Medical Waiver Certificate- Statement of Demonstrated Ability, due to congenitally short arms and contractures at the joints. The pilot demonstrated his ability during a medical flight test in a Cessna 150. During the test the pilot flew the airplane from the right seat as his right arm was stronger than his left. The pilot's brother stated the pilot flew the accident airplane from the right seat. The pilot's most recent logbook contained entries from October 19, 2004, through February 17, 2013. According to the logbook, the pilot had a total flight time of 539.1 hours, of which 53.4 hours were in the accident make and model of airplane. The pilot had recorded having 49.4 hours of night flight time. The airplane impacted the terrain in an open snow-covered field. The airplane continued to travel about 300 feet through the field, across a rural driveway, and into a wooded area where it came to rest. The wreckage path was along a 300 degree heading. First responders reported the smell of fuel was present near the main wreckage. The initial impact was about five feet long and contained pieces of green glass similar to the right wing navigational light. Approximately 15 feet to the west of the initial impact mark was an impact mark that was 3 feet long. Directly in front of and perpendicular to this mark was an 18 inch long slash mark in the snow. Just west of the 3 foot long mark was another ground impact mark that was approximately 5 feet long. Numerous pieces of wreckage were scattered between the initial impact mark and the main wreckage. These pieces included sections of both wings, the right wing lift struts, the upper engine cowling, the propeller ring gear, the baggage door, the right wing auxiliary fuel tank, the right main landing gear, the nose gear, and the propeller. The left main landing gear and the inboard sections of both wings were located near the main wreckage. The cockpit was destroyed by impact forces. The elevator trim control was set to a slight nose down trim setting. The trim cables were attached to the trim sprocket and were separated in the empennage. The flap control cables were attached to the flap control lever. The cables were separated at the pulleys in the fuselage. The aileron cables were connected to the chain drive which connected the control yokes. The chain drive remained connected to the left control yoke. The right control yoke was separated from the wreckage. The rudder control cables remained attached to the rudder crossover bar and the cables were separated in the aft fuselage area. The elevator control cables remained attached to the pulley chain in the cockpit and the cables were separated in the aft fuselage area. All of the separated control cables exhibited signatures consistent with overload separations. The fuel selector was positioned to the "Both" position. The fuel transfer switches were not located. The empennage was separated from the fuselage aft of the seats. The vertical stabilizer tubing was intact. The top portion of the rudder was separated and found along the wreckage path. The rudder balance weight remained attached to the top of the rudder. The left horizontal stabilizer and elevator remained attached to the empennage. The outboard section of the left si