2008 Aviate Raptor N74TK Accident Near Bealeton, Virginia

Accident Overview and Flight Details On May 23, 2008, at approximately 1133 eastern daylight time, an experimental light sport weight-shift aircraft, an Aviate Raptor with registration N74TK, collided with a tree and then the ground near Bealeton, Virginia. The flight was a personal, local operation under 14 Code of Federal Regulations (CFR) Part 91, departing from Warrenton Air Park (7VG0) in Warrenton, Virginia, at about 1120. Visual meteorological conditions prevailed, and no flight plan was filed. The aircraft sustained substantial damage, and the sole occupant, a commercial certificated pilot, was killed. ## Witness Accounts Witnesses provided varying descriptions of the event. One reported hearing the engine sputter and then fall silent, followed by the aircraft descending straight down. This witness noted a parachute above the wreckage that did not appear to be open and sketched the aircraft with wings in proper orientation. Another witness reported hearing a sound similar to gunfire upon impact and called 911. A third witness described the aircraft as spinning out of control and heard a small explosion. ## Pilot and Aircraft Information The pilot, age 43, held a commercial pilot certificate with airplane single engine land and instrument airplane ratings, as well as a sport pilot certificate with weight shift control land privilege. He held a third class medical certificate with no restrictions, and his last flight review was on November 8, 2007. His logbook showed approximately 329 total hours, with about 263 hours as pilot-in-command. He had logged approximately 7 hours in the accident aircraft since October 6, 2006. The aircraft, serial number AR00037, was reportedly built by the pilot in 1998 and registered with the FAA on July 10, 2007. It was powered by a Rotax 503 DCDI 50-horsepower engine and equipped with a Warp Drive two-bladed ground adjustable propeller. The aircraft also had a ballistic recovery system (BRS) BRS-5 Model 900 parachute. The last condition inspection was on August 27, 2007, at approximately 132.0 hours, with about 10 hours accumulated since then. ## Meteorological and Wreckage Findings A surface weather report from Culpeper Regional Airport (CJR) at 1120 indicated winds from 290 degrees at 4 knots, 10 statute miles visibility, clear skies, a temperature of 19 degrees Celsius, a dew point of 08 degrees Celsius, and an altimeter setting of 30.03 inches of Mercury. The accident site was approximately 6 nautical miles and 066 degrees from CJR. The crash site was along a tree line about 5.6 nautical miles southeast of the departure point. The wing remained suspended in a tree, with most wreckage at the base. The ballistic parachute was deployed and found next to the wreckage. The engine had separated from its mount. During recovery, it was noted that the nose wires were not connected to the attach point of the nose hinge, and a snap hook used to secure them was not located. ## Structural and Mechanical Examination Friends of the pilot examined the wreckage and showed the FAA inspector-in-charge their findings, supported by photographs. Impact damage was present on all major structural components. The stainless steel nose hinge attach point tang was not fractured. The backhaul cables connecting to the rear of the crossbar hinge and rear of the keel were fractured close to the crossbar hinge, with gouges on the crossbar hinge consistent with the fracture location. Both upper side wires and both tail wires were fractured, while both lower side wires connecting the control frame to the crossbar were not fractured. The backstay was fractured near the kingpost attach point. The BRS parachute handle was armed but not activated, though the firing cable appeared pulled adjacent to the rocket motor. A portable GPS receiver was retained for examination. Engine examination by a manufacturer representative with FAA oversight showed crankshaft continuity during hand rotation, with suction and compression in each cylinder. Spark plugs were only finger tight, with electrode gaps measuring 0.028 inch (specification 0.020 inch). One carburetor was set too high, with no other fuel system anomalies noted. The propeller, which remained attached to the engine, had one blade fractured 16 inches from the hub and the other fractured 6 inches from the hub. ## Medical and Pathological Information A postmortem examination by the Office of Chief Medical Examiner Northern Region, Fairfax, Virginia, listed the cause of death as traumatic injuries. Forensic toxicology by the FAA Bioaeronautical Sciences Research Laboratory in Oklahoma City, Oklahoma, was negative for carbon monoxide, cyanide, volatiles, and tested drugs. The Commonwealth of Virginia Department of Forensic Science found the blood specimen negative for ethanol and tested drugs, and the vitreous humor specimen negative for methanol, acetone, and isopropanol. ## GPS Data and Designer Input The Safety Board’s Vehicle Recorders Division read the GPS receiver, which recorded data from takeoff to within 0.01 nautical mile (approximately 61 feet) of the accident site. The flight departed 7VG0 to the northwest, made a left turn, then proceeded southeast until 1121:19, when a left 280-degree turn was followed by a right 374-degree turn. A left 720-degree turn then occurred, and between 1127:43 and 1132:57 (last GPS data), the flight proceeded southeast. Between 1131:50 and 1132:51, heading and ground speeds remained consistent. Between 1132:51 and 1132:57, ground speed slowed from 51 to 15 miles per hour. An aircraft designer representative stated that if the snap hook securing the nose wires to the nose hinge plate separated in flight, the A-frame would fold back and side cables would pull the wings down (anhedral), causing tremendous compression loads on the crossbar and hinge. This would shift the center of gravity very far forward, resulting in an unrecoverable dive. NTSB review of pictures of the crossbar and hinge showed no evidence of appreciable damage. Service Bulletin 22005/1, which called for installation of a nose catch safety cable at the nose hinge no later than May 31, 2005, was not installed on the accident aircraft. The representative noted the bulletin was in response to an accident in South Africa involving another make of trike, where nose wire separation was not conclusively proven. The manufacturer had used the same type nose cable attachment for many years without failure, but changed the nose attachment system in later years due to difficulty clipping the snap hook into the tang when the wing was under tension, as the keel tube was double sleeved in trikes and single tube in hang glider type aircraft.