Paris, TN, USA
N101GP
Dragon Fly Aviation GT-500
The certificated commercial pilot was the first registered owner of the amateur-built light sport airplane, but he did not build the airplane. On the day of the accident, after two aerial application flights, he returned to his airport to replenish the application chemical for a third trip to the same agricultural field. About 30 minutes later, a witness heard the engine "sputter" during a spray run, and observed the airplane begin a climbing right turn back towards the airport. The engine stopped and restarted, and the airplane began another climb in the direction of the airport. The engine stopped a second time, and two witnesses saw the airplane descend without engine power into a wooded area. The airplane was substantially damaged, and the pilot was fatally injured. Autopsy results indicated that the pilot had diabetes, coronary artery disease, an enlarged heart, and gallstones. In addition, he was taking a medication commonly prescribed for neurological pain, and another for smoking cessation, both of which had the potential to cause distraction or impairment. It was not clear what role, if any, the medical conditions or medications played in the accident. He did not note any medications or medical conditions on his most recent application for medical certificate, but it is possible that the medications were initially prescribed since that application. At the time of the accident, the airplane and engine had accumulated approximately 89 hours since new. The pilot had previously experienced engine stoppage problems, and had conducted at least one forced landing due to an engine stoppage. Subsequent to that forced landing, and in the weeks just prior the accident, the pilot installed an electric fuel pump, which was in addition to the existing engine-driven fuel pump. Post-accident examination of the airplane indicated that the engine fuel system was not configured or equipped in accordance with the engine manufacturer's published guidance. Differences included fuel lines that were not thermally shrouded, lack of a fuel pump bypass circuit, lack of a fuel return line, and pump output pressure which exceeded the engine manufacturer's limits. The engine manufacturer's guidance contained multiple statements that such differences could result in engine problems and/or stoppage.
HISTORY OF FLIGHT On April 21, 2008, about 0950 central daylight time, an experimental amateur-built Dragon Fly Aviation GT-500, N101GP, was substantially damaged when it impacted trees and terrain near Paris, Tennessee. The certificated commercial pilot was fatally injured. The local aerial application flight was being operated under the provisions of 14 Code of Federal Regulations (CFR) Part 137. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. According to witnesses, about 0800 on the day of the accident, the pilot departed from his private home airstrip, flew to a wheat field approximately 5 miles to the southwest, and completed one aerial chemical application flight. The pilot then returned to his airstrip. About 0845, a witness saw the pilot depart from the airstrip the second time, and awaited the pilot’s return. About 0915 the pilot returned for refueling and chemical replenishment. According to the witness, the pilot was concerned about the engine oil pressure, and stated that it was approximately "20 pounds less than it should be." The pilot and the witness checked the oil quantity, and confirmed it was "full." The pilot began loading the chemical, and the witness left the airstrip. About 0930 the airplane returned to the wheat field and resumed the aerial application. According to another witness located west of the wheat field, about 0950, the airplane was flying south, when the engine "sputtered" approximately mid-way through a spray run. The chemical spray stopped, and the airplane began a climbing right turn to the north. The engine stopped when the airplane was approximately 800 feet above the field on a northerly heading. The engine restarted, and the airplane began to climb, still on its northerly heading. When the airplane was at approximately 900 feet, the engine "sputtered" and stopped a second time. The airplane descended while it continued on the northerly heading, which took it over a wooded area. Another witness located north of the wheat field also heard the engine stop, restart, and stop a second time. She and the previous witness both saw the airplane disappear from view when it was in an engine-out glide over the wooded area, and heard the sounds of impact shortly thereafter. First responders to the accident indicated that the pilot occupied the front seat, and that he was not wearing a helmet. His five-point restraint harness was buckled, but the shoulder straps were found behind/under his arms and shoulders. PERSONNEL INFORMATION The accident pilot held commercial pilot, flight instructor, and 14 CFR Part 137 (Private) operating certificates, and he had accumulated approximately 9,000 total hours of flight experience. His most recent Federal Aviation Administration (FAA) second-class medical certificate was issued in December 2006. AIRCRAFT INFORMATION FAA records indicate that the airplane serial number was 397. The airplane was equipped with a Rotax 912 ULS non-certificated engine, and the engine serial number was 5644471. FAA documents indicate that the airplane was first registered to the accident pilot in December 2005, and that the initial airworthiness certificate, also in the accident pilot's name, was issued in February 2006. As of the date of the accident, the airplane and engine had accumulated a total time in service of about 89 hours. METEOROLOGICAL INFORMATION The 0955 weather observation at an airport located approximately 47 miles northeast of the accident location reported winds from 100 degrees at 5 knots, 7 miles visibility, clear skies, temperature 18 degrees C, dew point 11 degrees C, and altimeter setting of 30.08 inches of mercury. WRECKAGE AND IMPACT INFORMATION According to information provided by the FAA and local law enforcement personnel, the accident site was located in a wooded area approximately 1 mile north of the subject wheat field. The accident site was located between the wheat field and the accident pilot's home airstrip. There was no significant horizontal dimension to the wreckage path; the wreckage was tightly contained, and the surrounding trees exhibited minimal damage. The trees were spaced approximately 20 to 30 feet from one another, and were approximately 30 feet tall. The pilot was seated in the front seat, and the chemical hopper was located where the rear seat was normally located. All airplane components were found at the site. The fuselage was oriented on its left side, approximately 20 degrees nose down. The forward portion of the fuselage was partially fractured and crushed. The wings and tailboom exhibited significant impact damage. The fuel system was not compromised, and there were no fuel leaks. FAA and recovery personnel estimated that approximately 2 gallons remained in each fuel tank. The engine and propeller did not exhibit any impact damage. The flap handle had four positions, and was in the aft-most position, corresponding to the full flap deflection of 30 degrees. The flaps were also in the full-down position. The Hobbs meter installed in the airplane indicated a time of 88.6 hours. Residual chemical remained in the hopper. There were no indications of pre- or post-impact fire. MEDICAL AND PATHOLOGICAL INFORMATION The Henry County Medical Examiner, Tennessee Department of Health and Environment, conducted an autopsy on the pilot. The cause of death was cited as "multiple blunt force injuries." The medical examiner’s report noted that the pilot had a "history of diabetes and a cardiac history of unknown etiology, an enlarged heart, severe coronary artery disease, and gallstones." Toxicological testing of the pilot's tissue samples was conducted by the FAA Civil Aero Medical Institute, and gabapentin, varenicline and atenolol were detected. The pilot’s most recent application for 2nd class Airman Medical Certificate, dated 12/27/2006, noted “No” to “Do You Currently Use Any Medication,” and to all conditions under “Medical History,” including specifically “Heart or Vascular Problems,” “Diabetes,” “Neurological disorders,” and “Mental disorders of any sort; depression, anxiety, etc.” “Total Pilot Time” was noted as “Approx. 9000” hours “To Date” and 45 hours in the “Past 6 Months.” ADDITIONAL INFORMATION Registration and Airworthiness Documentation According to one FAA Form 8050-2, "Aircraft Bill of Sale," the initial sale was from Quicksilver Manufacturing to Dragon Fly Aviation. The form had the pre-printed word "Aircraft" struck out, and the word "Kit" typed in front of "Aircraft." The sale date on the form was listed as February 28, 2005, and the "In testimony whereof" date was listed in as July 7, 2005. The form also bore a stamped notation in the "For FAA Use Only Block" of "Dec 13 2005." According to another FAA Form 8050-2, "Aircraft Bill of Sale," the airplane was sold from Dragon Fly Aviation to the accident pilot. The pre-printed word "Aircraft" was not struck out or overwritten on this form. Both the sale date and the "In testimony whereof" date on the form were listed as July 8, 2005. The form also bore a stamped notation in the "For FAA Use Only Block" that stated "Conveyance Recorded 2005 Dec 13." According to an Affidavit of Ownership (FAA Form 8050-88), the builder and owner of the airplane were both cited as "Dragon Fly Aviation," and the box accompanying the statement "More than 50% of the above-described aircraft was built from a kit (prefabricated parts) and I am the owner" was selected. The form was notarized on July 14, 2005. The form also bore a stamped notation "Conveyance Recorded 2005 Dec 13." Wing Washout Adjustments Wing washout is a deliberate twist in both wing panels which provides the outboard wing sections with a lower angle of incidence than the root sections. Wing washout primarily affects airplane stall characteristics by enabling the wing root section to stall prior to the outboard section, thereby retaining lateral controllability further into the stall. Asymmetric washout can result in objectionable roll consequences, such as wing drop or loss of roll control, in the stall regime. Threaded rods that screwed into the lift struts were used to independently adjust the washout of each wing. The adjustment rods for the left and right lift struts were not set so that an equal number of threads were exposed on each rod, which was indicative of the possibility of dissimilar washout angles for the left and right wings. The Quicksilver Installation Instructions (QII) specified that jam nuts were to be used to secure the strut adjustments, but the jam nut on the left wing strut rod was loose. Engine General Preliminary visual inspection of the engine did not reveal any obvious external damage, and the throttle and choke cables were intact and functional. Impact damage to the throttle quadrant prevented full travel of the throttle. The FAA inspector reported that shortly after the accident, he checked the oil cap at the accident site. He stated that it was securely attached, and when he removed it to check the oil quantity, oil started to leak out, so he re-installed the cap. Several days after the accident, an oil film was observed on the same side of the engine as cylinder numbers one and three, but no oil leaks were found on the engine. The dry sump oil system was found to be overfilled, and the observed oil film was consistent with oil being vented from the vent line due to an overfilled oil tank. The engine was fitted with an aftermarket thermostatic oil by-pass valve. This component was not specified in, or required by, either the Rotax Installation Manual (IM) or the QII. Rotax Maintenance and Servicing Guidance On December 22, 2006, Rotax issued Service Instruction (SI) 912-017, which specified installation of air filters equipped with provisions for safety-wiring, and inspection of certain air filter installation orientation. The SI stated that improper air filter installation "may lead to problems in fuel distribution and may damage the engine," and that air filters had to be safety wired to prevent inadvertent separation. The SI applied to the accident engine. The air filters that were installed on the engine were not secured by safety wire, but did remain securely installed during the flight and impact sequence. The air filters were not subject to the "orientation" portion of the SI. On April 13, 2007, Rotax issued Mandatory Service Bulletin (SB) 912-053UL, which specified replacement of the engine fuel pump. The accident airplane engine was not subject to SB 912-053UL, by virtue of its serial number. On May 29, 2007, Rotax issued Mandatory SB 912-054UL, entitled "Checking or Replacement of Flexible Fuel Line." The accident airplane engine was not subject to SB 912-054UL, by virtue of its serial number. On April 15, 2008 (6 days prior to the accident) Rotax issued Service Letter SL 912-014 R1, entitled "Use of Rotax Unapproved Engine Components or Accessories for Rotax Aircraft Engines." The SL specifically stated that a "non-genuine Rotax" oil filter which lacked a bypass feature that "could lead to a completely blocked oil system." The SL applied to the accident engine, but the investigation did not determine whether the installed oil filter was approved by Rotax. Fuel System Configuration According to the Quicksilver GT500/912 Airplane Flight Manual (AFM), the total fuel quantity was 16 gallons, contained in two 8 gallon tanks. The total unusable fuel quantity was cited as 2.25 gallons. Each fuel tank was equipped with a shutoff valve mounted at the tank outlet. The fuel lines from each shutoff valve were routed to a fuel selector valve, and from there, a single fuel line was routed to the fuel pumps and engine. One fuel line was routed from each fuel tank to a "T" fitting, from which a single line was routed to the electric fuel pump. Downstream of the electric fuel pump, a line was routed across the top of the engine to the engine-driven pump. An output line was routed from the engine-driven pump to the fuel manifold, and from there one line was routed to each of the two carburetors. Examination of the engine and airplane revealed that all the fuel lines were clear, flexible plastic material. The only fuel lines that were sleeved were the two lines from the fuel manifold to the carburetors. The fuel lines from the fuel manifold to the each of the carburetors were routed within approximately 1/2 inch of the exhaust pipes. The Rotax IM and the Illustrated Parts Catalog (IPC) for the 912 series engines both specified a fuel return line from the fuel manifold to the fuel tank(s). The Rotax Operator's Manual stated that "the fuel return line serves to avoid formation of vapour lock." Neither the Quicksilver QII nor the AFM fuel system schematic depicted the fuel return line. The airplane was not equipped with the required fuel return line from the fuel manifold to either of the fuel tanks. The Rotax IM defined a "caution" as "an instruction which, if not followed, may severely damage the engine or other component." The Rotax IM contained the following caution: "For prevention of vapour locks, all the fuel lines on the suction side of the fuel pump have to be insulated against heat and fire in the engine compartment and routed at distance from hot engine components." The QII also specified that sleeving was to be installed on the fuel line. The fuel line from the electric fuel pump to the engine-driven fuel pump was not in compliance with the published guidance. The installed fuel filter utilized a paper element, which was contrary to the Rotax IM. No fuel contamination was noted. Both carburetor float bowls were clean. The wing tank fuel shut-off valve was function-checked. While the stops permitted a handle travel of 90 degrees, the valve completely shut off fuel flow after handle travel of 35 degrees. The Quicksilver GT500/912 AFM specified that the engine was to use either "premium grade" or "Euro-Super RON 95" automotive gasoline. It also approved the use of 100LL aviation gasoline, but with an advisory to "Only use aviation fuel when the listed automotive fuels are not available." The actual fuel type in the airplane was not determined. Electric Fuel Pump According to the pilot’s sons, the airplane was originally equipped with only an engine-driven fuel pump, but the pilot later fitted an additional electric fuel pump. The pilot had previously experienced engine stoppage problems, and had conducted at least one forced landing due to an engine stoppage. Subsequent to that forced landing, and in the weeks just prior the accident, the pilot installed the electric fuel pump. The Rotax IM specified an electric fuel pump in series with, and prior to the engine-driven pump. The IM stated that the electric pump was required "in case of a malfunction or defect" of the engine-drive pump, and was also required to preclude vapor lock of the fuel supply to the engine-driven pump. The IM installation diagram depicted a fuel bypass circuit around the electric pump, but the accident airplane was not plumbed in accordance with this diagram. Neither the Quicksilver QII nor the AFM contained any references to an electric fuel pump. The Rotax IM defined a "Warning" as "an instruction which, if not followed, may cause serious injury, including the possibility of death." Section 14.2 of the Rotax IM cited the minimum, normal, and maximum fuel pressure limits as 2.2, 4.4 and 5.8 pounds per square inch (psi), and that the pressures were to be measured at the fuel manifold. The IM contained the warning that fuel pressure in excess of the stated limit can lead to an override of the float valve, and "subsequent engine stop." The IM also noted that "If an electrical auxiliary pump is installed, the whole fuel system has to be designed to warrant engine operation within the specified pressure limits." Finally, the IM contained the caution that "the fuel pressure of an additional auxiliary fuel pump should not exceed... 4.4 psi." The airplane was not equipped with a fuel pressure gauge. The electric fuel pump was plumbed in series with, and prior to, the engine-driven pump. The new pump was
A fuel system configuration that was not in accordance with the engine manufacturer's published guidance, which resulted in a complete loss of engine power due to fuel starvation.
Source: NTSB Aviation Accident Database
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