CEN18FA030

The loss of engine power due to fuel starvation, which resulted from the unporting of the fuel during a right turn due to the auxiliary fuel tanks' improper configuration.

The airline transport pilot departed on a cross-country flight to relocate his newly-purchased airplane to his home state. A fixed-based operator employee at the airport reported that the pilot overflew the airport and requested verification that his landing gear were extended. The employee confirmed that they were down. After overflying the runway the airplane descended and impacted trees and terrain. Another witness reported that after the low pass, the airplane started to climb and then turned right at an altitude of 250 to 300 ft above ground level. He added that as the airplane turned, its tail "wobbled," which he attributed to a loss of engine power. Then the nose pitched down before it descended below the tree line. The airplane separated into several pieces, and the forward fuselage and engine came to rest inverted behind the empennage. The signatures on the propeller were consistent with little or no power at the time of the accident. A postaccident examination of the engine, airframe, and flight controls revealed no preimpact anomalies that would have precluded normal operations. Investigators were not able to ascertain why the pilot asked for verification of the landing gear position. The landing gear were found retracted in the airplane wreckage. The airplane had been equipped with an aftermarket auxiliary fuel tank system; however, the system installed did not match the specifications of the supplemental type certificate (STC) identified in the maintenance logbooks or any other STC approved for the make and model of the airplane. The system had been installed about 9 years before the accident and before the pilot had purchased the airplane. The airplane had only flown about 4.5 hours since the fuel tanks were installed. The auxiliary fuel tanks were not vented properly which could have resulted in a vacuum preventing fuel flow through the lines and to the engine. In addition, neither auxiliary fuel tank was equipped with a fuel pickup line inside of the tank. During a turn into the selected fuel tank it is possible that the fuel could unport resulting in fuel starvation and a loss of engine power. The fuel selector valve was selected to the main tank which was empty; however, it is unknown what position change the pilot may have made following the loss of engine power. Evidence of fuel was found in the fuel lines and fuel pump following the accident. Although the amount of fuel onboard the airplane could not be determined, this evidence indicates there was likely sufficient fuel and that fuel exhaustion did not occur. Given the configuration of the auxiliary fuel tanks, the engine likely lost power due to fuel starvation. This resulted from the unporting of the fuel due to the auxiliary fuel tank's improper configuration and occurred during the right turn the airplane entered after the low pass over the airport.

The Louisiana Forensic Center, LLC., Youngsville, Louisiana, performed the autopsy on the pilot on November 10, 2017, as authorized by the Rapides Parish Coroner's office. The autopsy concluded that the cause of death was "blunt force injuries to head," and the report listed the specific injuries. The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological tests on specimens that were collected during the autopsy. The results were negative for all tests conducted. The pilot held type certificates for the Boeing 727 and the North American Sabreliner. At the time of his medical certificate application, the pilot estimated his total flight time as 5,000 hours; 15 hours of which were logged in the previous 6 months. The certificate contained the limitation "Must wear corrective lenses for near and distant vision." The pilot's family provided a scanned copy of several pages from the pilot's flight logbook; with entries dated between August 8, 2015, and October 26, 2017. A review of the logbook indicated that the pilot had logged no less than 2,102.2 hours. In 2015 the pilot had logged 12.5 hours in the make and model of the accident airplane. He did not have any logged flight time, in the make and model of the accident airplane, within the 6 months before the accident. The accident site was located in heavily forested terrain about 0.4 mile northeast of the departure end of runway 36. The accident site was at an elevation of 125 ft mean sea level and the main wreckage came to rest inverted on a heading of 60°. The main wreckage included the inboard sections of the left and right wings, the fuselage, the left elevator, the horizontal stabilizer, the rudder, the vertical stabilizer, and the engine and propeller assembly. The engine and fuselage forward of the seats separated from the aft section of the fuselage and came to rest inverted behind the empennage. The outboard section of the left wing was found about 140 ft from the main wreckage. The top portion of a tree directly above this piece of the left wing was impact damaged and separated. The outboard section of the right wing, sections of canopy, the right elevator, ailerons, flaps, sections of cowling, and a section of the throttle were found in trees and on the ground between the outboard section of the left wing and the main wreckage. All major components of the airplane were located. Flight control cables were traced from the cockpit to the ailerons, elevator, and rudder. All observed separations points exhibited signatures consistent with impact damage and overload separation. The elevator trim tab was found in a neutral position. The pitch trim motor was operational when electric power was applied to it. The main landing gear were found retracted. Material consistent with wood splinters were found in the right-side jack pad and a pine branch was found in the right wheel well. The landing gear selector handle was found in its up position and its control shaft was continuous from the selector to the hydraulic pump assembly. The hydraulic pump and its solenoid were operational when electric power was applied to the solenoid. Cockpit mixture and propeller governor controls were manipulated by hand and their respective engine linkage moved accordingly. The liberated throttle control was placed back into its cockpit location and pressed into its forward position and the engine throttle linkage moved forward. The engine throttle linkage was moved rearward and the cockpit throttle control moved out of its forward position. The engine driven fuel pump line to the fuel servo was broken off at the pump. A liquid consistent with the smell of aviation gasoline exited the line when it was moved. The outboard section of one propeller blade was bent rearward and the other blade was not bent. The blades did not exhibit any leading-edge nicks or chordwise abrasions. The fuel selector was found positioned on the main tank. Detents on the fuel selector valve were firm and an audible click could be heard at each detent. The electric fuel pump fuel line was torn and a liquid consistent with the smell of aviation gasoline exited the line when electric power was applied to the electric fuel pump. Both auxiliary fuel tanks were impact damage and separated from each wing. Investigators were unable to establish how much fuel was in each tank at the time of impact. The main fuel tank was not compromised and was empty. No contaminants were noted in the fuel lines or fuel screens that would have occluded fuel flow. First responders reported that a small amount fuel leaked or dripped from the airplane when they arrived on scene; however, it is unknown how much fuel was on board at the time of the accident. No mechanical anomalies were noted with the airframe or flight controls that would have precluded normal operation. Engine Examination The engine No. 4 cylinder was impact damaged on the exhaust valve side of the cylinder. The top bank of spark plugs, p-leads, fuel pump, vacuum pump, propeller, and valve covers were removed to facilitate the examination. A mud dobber nest was observed on the inboard portion of the propeller flange. The spark plug points exhibited darker, sooty deposits consistent with a rich(er) mixture. The p-lead from the right magneto on the No. 4 cylinder was impact damaged and separated at the upper spark plug. The p-leads from the left magneto on the No. 1 and 3 cylinders were impact-damaged and separated. The engine was rotated through by hand at the propeller flange. Valve movement, and drive train continuity was observed at the accessory case and on all four cylinders. Air movement was documented tactilely at the spark plug orifice on all four cylinders. Both magnetos were removed from the engine for further examination. Three of the four left magneto leads exhibited a spark when the unit was actuated by hand. The fourth lead was impact damaged at the cap and could not be functionally tested. The cap was removed, and the unit was rotated by hand; spark was observed at the point of the impact damaged lead. All four leads on the right magneto exhibited a spark when the unit was actuated by hand. The spline on the vacuum pump was unremarkable. When actuated by hand, the unit rotated without resistance and suction and compression were obtained. No mechanical anomalies were noted with the engine that would have precluded normal operation. The airplane was manufactured and issued the original airworthiness certificate in 1948 under the Civil Air Regulations Part 4a. Neither a Pilot Operating Handbook nor an Airplane Flight Manual were required; and therefore, performance-specific data such as fuel consumption was not available. In addition, the FAA major repair and alteration records available for the airplane indicated the airplane had been modified multiple times to include a powerplant change and landing gear changes. According to the weight and balance document located in the wreckage and dated January 8, 2003, the airplane could hold 215.7 lbs or 35.95 gallons of fuel, with the most aft center of gravity loading. The datasheet for the engine provided a fuel consumption range of 8.5 to 11 gallons per hour. If the fuel tanks were full, the airplane had a range between 3 and 4 hours depending on the fuel/air mixture settings controlled by a pilot in flight. Fuel System The airplane was equipped with an aftermarket auxiliary fuel tank system; one tank in each wing. The fuel lines ran from each respective fuel tank inboard to the fuel selector valve. The airplane was equipped with a two-part main tank. The main tank fed through 1 ¼ inch tubing into a header tank and then to the fuel selector valve. The routing then continued to the gascolator, to the fuel pump, and then toward the engine. Each auxiliary tank was equipped with a copper vent line that ran through the length of the fuel tank. One end of the c