Denton, TX, USA
N767GW
DAVIS JOHN TR-4
Shortly after clearing the airplane for takeoff, the air traffic tower controller noticed that the airplane’s climb did not appear to be normal. The airplane appeared to descend, bank to the right, and then disappear behind a line of trees. The airplane impacted the ground near a set of power lines and a postcrash fire ensued. The pilot recalled little about the events leading up to the accident. He did report that the engine lost power. The postcrash fire consumed part of the cabin area and thermally damaged the engine’s electrical components, so an examination of the fire-damaged electronic ignition and fuel control systems could not be conducted. Further examination of the engine, airframe and other airplane systems failed to identify any preimpact abnormalities. A review of the airplane's records indicated that the pilot was having weight and balance issues with the airplane. The pilot had to add aft ballast to compensate for a nose-heavy condition. The reason for any potential loss of engine power and for the loss of control could not be determined.
HISTORY OF FLIGHT On July 18, 2010, about 1920 central daylight time, a single-engine TR-4 kit-built airplane, N767GW, collided with terrain after a loss of control, shortly after departure from the Denton Municipal Airport (DTO), Denton, Texas. The private rated pilot received serious injuries and the passenger was fatally injured. The airplane was substantially damaged and a postcrash fire ensued. The airplane was registered to and operated by a private individual. Day visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight was originating at the time of the accident. The control tower operator reported that the airplane was cleared for takeoff and the airplane departed the runway; before the airplane disappeared from sight, he observed that the airplane was not gaining altitude. The controller added, it appeared that the airplane began to lose altitude, made a bank to the right, and disappeared behind a line of trees. The airplane collided with the ground approximately one mile southwest of the airport. A pilot statement was received on August 2, 2011. The pilot stated that he had limited memory of the accident, but remembers during climbout, the engine apparently lost power. He added that the angle-of-attack annunciator, indicated a high angle of attack and the airplane veered right. The pilot further stated that he lowered the nose of the airplane to establish a glide, and that he had a very hard and rough landing. PERSONNEL INFORMATON The pilot held a private certificate for airplane single-engine land. The pilot was issued a third class Federal Aviation Administration (FAA) medical, on April 2, 2010. A review of the pilot’s logbook revealed that he had accumulated a total of 125.9 flight hours, with 34.7 hours in the accident airplane. In addition, the last entry in the pilot’s log was dated October 25, 2009. AIRCRAFT INFORMATION The four seat, low-wing, tricycle-gear airplane, was built from a kit and was constructed primarily of composite material. The airplane was equipped with a Subaru H6 engine, expected to produce about 195 horsepower, driving an MT 3-bladed, constant speed propeller. According to FAA records, the kit was manufactured by TRI-R Technology, sold to a buyer in December 1995, and the kit was delivered in March, 1996. From 1995 to 2001, the kit changed owners two more times; before the fourth buyer purchased the kit in July, 2004. The fourth buyer completed the kit and the airplane was issued an experimental, amateur-built airworthiness certificate on January 27, 2006. During the initial test flight, the airplane was not able to take off from the runway. It was determined that the airplane had a nose-heavy condition and elevator control was not effective enough to counter the forward weight condition. Reportedly, after the addition of 120 pounds of rear ballast, the airplane was able to depart the runway. It’s unknown what modifications, if any, were applied to the airplane to permanently correct the forward center of gravity condition. A review of the airplane’s maintenance records did reveal that in July, 2006, at a tachometer reading of 54.1 hours, 15 pounds of lead ballast was added to the airplane. Additionally, a person familiar with the airplane stated the accident pilot had to approach the runway at 90 knots, instead of a normal 65 knots, to prevent the airplane from experiencing a hard landing. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board (NTSB) and inspectors from Federal Aviation Administration (FAA) examined the airplane wreckage on-site. All major components of the airplane were accounted for at the scene. The main wreckage came to rest in the upright position, about 156 feet beyond a set of powerlines. An impact ground scar consistent with the right wing tip, started about 75 feet prior to the powerlines. A larger ground scar, consistent with the fuselage, started about 45 feet prior to the powerlines. The right wing and elevator separated from the fuselage and were located beyond the main wreckage. The three bladed propeller hub remained attached to the engine; however, each blade was splintered and had separated from the hub. A postcrash fire consumed part of the fuselage. TESTS AND RESEARCH A postaccident examination of the recovered airframe and engine was conducted at the facilities of Air Salvage of Dallas (ASOD). The airplane was powered by an automotive six-cylinder engine adapted for aircraft use. A sparkplug from each cylinder was removed; the sparkplugs were absent of any abnormalities. The engine was rotated by hand; continuity was established through the engine. A thumb compression and suction test was conducted on each cylinder. The engine’s electrical system, including the electronic ignition and fuel control systems were damaged by the postcrash fire and could not be examined. No evidence of pre-impact mechanical malfunction was noted during the examination of the engine or the airframe. The electrically controlled, three-bladed constant-speed propeller was separated from the engine and taken to a local propeller shop for disassembly and inspection. The DC electric motor that controlled the blades pitch would not operate. Further disassembly of the electric pitch-change motor and separation of the motor from the gear box, disclosed that when electrical current was applied to the electric pitch change motor, the motor operated. The electric motor and gear box assembly was sent to the NTSB Materials Laboratory in Washington, D.C., for further examination. The Materials Laboratory did not find any indication of pre-accident abnormalities with the assembly. Disassembly of the propeller hub revealed that the blade pitch assembly moved through a range of motion. The exact pitch angle on the propeller blades at the time of the accident could not be determined; however, it was noted after moving the blades through their range of motion, the blades, as found, appeared to be near the low pitch (high rpm) setting.
A loss of engine power and the pilot’s subsequent loss of control for undetermined reasons.
Source: NTSB Aviation Accident Database
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