History of Flight
On July 18, 2010, at approximately 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 Denton Municipal Airport (DTO), Denton, Texas. The private-rated pilot sustained serious injuries; the passenger was fatally injured. The airplane was substantially damaged, and a postcrash fire ensued. Day visual meteorological conditions prevailed, and no flight plan was filed for the personal flight under 14 CFR Part 91.
The control tower operator reported that the airplane was cleared for takeoff and departed the runway. Before the airplane disappeared from sight, the operator observed that it was not gaining altitude. The airplane appeared 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 received on August 2, 2011, indicated limited memory of the accident. The pilot remembered that during climbout, the engine apparently lost power. The angle-of-attack annunciator indicated a high angle of attack, and the airplane veered right. The pilot lowered the nose to establish a glide and reported a very hard, rough landing.
Personnel Information
The pilot held a private certificate for airplane single-engine land and was issued a third-class FAA medical certificate on April 2, 2010. Review of the pilot's logbook revealed a total flight time of 125.9 hours, with 34.7 hours in the accident airplane. The last logbook entry was dated October 25, 2009.
Aircraft Information
The four-seat, low-wing, tricycle-gear airplane was built from a kit primarily of composite material. It was equipped with a Subaru H6 engine (expected to produce about 195 horsepower) driving an MT three-bladed constant-speed propeller. According to FAA records, the kit was manufactured by TRI-R Technology, sold in December 1995, delivered in March 1996, and changed owners twice before being purchased by the fourth buyer in July 2004. The fourth buyer completed the kit, and an experimental, amateur-built airworthiness certificate was issued on January 27, 2006.
During the initial test flight, the airplane could not depart the runway due to a nose-heavy condition; elevator control was insufficient to counter the forward weight. After adding 120 pounds of rear ballast, the airplane was able to depart. It is unknown what modifications, if any, permanently corrected the forward center of gravity. Maintenance records indicated that in July 2006, at a tachometer reading of 54.1 hours, 15 pounds of lead ballast was added. A person familiar with the airplane stated that the accident pilot had to approach the runway at 90 knots instead of the normal 65 knots to prevent a hard landing.
Wreckage and Impact Information
NTSB and FAA inspectors examined the wreckage on-site. All major components were accounted for. The main wreckage came to rest upright about 156 feet beyond a set of powerlines. An impact ground scar consistent with the right wing tip began about 75 feet before the powerlines; a larger fuselage scar began about 45 feet before them. The right wing and elevator separated from the fuselage and lay beyond the main wreckage. The three-bladed propeller hub remained attached to the engine, but each blade was splintered and separated. A postcrash fire consumed part of the fuselage.
Tests and Research
Postaccident examination of the recovered airframe and engine was conducted at Air Salvage of Dallas. The engine, an automotive six-cylinder adapted for aircraft use, had sparkplugs removed from each cylinder; they showed no abnormalities. Hand rotation established engine continuity, and thumb compression/suction tests were normal. The engine's electrical system, including electronic ignition and fuel controls, was damaged by fire and could not be examined. No evidence of pre-impact mechanical malfunction was found in the engine or airframe.
The electrically controlled constant-speed propeller was separated and taken to a propeller shop. The DC electric motor controlling blade pitch would not operate initially. After disassembly and separation from the gearbox, the motor operated when current was applied. The assembly was sent to the NTSB Materials Laboratory, which found no pre-accident abnormalities. Disassembly of the hub showed the blade pitch assembly moved through a range of motion. The exact pitch angle at impact could not be determined, but the blades appeared near the low pitch (high rpm) setting.