Jackson, WY, USA
UNREG
CGS Aviation Hawk Two Place Arrow
Several witnesses reported that the airplane departed runway 19, and immediately climbed to approximately 500 feet above ground level (agl), while maintaining runway heading. The airplane then turned left onto the crosswind leg of the traffic pattern and maintained a slight climb. One witness, who was in a vehicle, observed the airplane in normal flight on a left downwind for runway 19 at an altitude of 800 to 1,000 feet. The witness observed the airplane turn left (west) onto the base leg for runway 19 "in normal flight and was descending but not what appeared to be abnormal." The airplane continued its nose-low descent toward the terrain until approximately 200 feet agl, the airplane began a "steeper" nose-low descent toward terrain. The airplane then impacted terrain in a wings level attitude, bounced, nosed over, and came to rest inverted. During the descent, the witness did not noticed any movement of the elevator or other flight control surfaces, or any in-flight structural failure of the airplane. The accident flight was the third flight conducted by the pilot since he had completed repairs after sustaining a hard landing with the airplane. In order to complete the repairs to the airplane, the pilot had to removed the elevator and aileron controls located in the boom tube. NTSB materials laboratory examination of the aileron and elevator controls revealed no features or marks were found at a location of approximately 5/16-inch forward of the original location of the rear locking collar on the torque tube surface, with the exception of two distinct circumferential marks. The featureless surface, confirmed by testing, indicated that the locking collar was slightly torqued and that the torque tube had moved relatively slowly over this distance, possibly with two stops. The torque required to loosen the rear locking collar screw was measured at 3-inch pounds, representing a minimal snugging of the collar bolt and collar on the torque tube. According to the manufacturer, a 3/16-inch aft movement of the torque tube would be enough to lose any tension in the elevator control cables. The rear edge of the cutout on the boom tube for the rear control stick displayed three locations where paint had been removed, but there was no material deformation. The lack of deformation is consistent with light contact by the control stick, which would be expected if the control stick had been pulled rearwards manually. A lightly rubbed area on the aileron crank revealed laterally orientated arced lines on the surface and corresponding laterally orientated smeared surface on the upper front bulkhead tube. No evidence was found to indicate that an inspection mirror had been trapped in the boom tube.
HISTORY OF FLIGHT On June 27, 2005, approximately 1225 mountain daylight time, an unregistered CGS Aviation Hawk Two Place Arrow experimental light-sport airplane was destroyed when it impacted terrain following an uncontrolled descent during the base leg of the visual approach to runway 19 at Jackson Hole Airport (JAC), Jackson, Wyoming. The commercial pilot, who was the sole occupant and owner of the airplane, sustained fatal injuries. Visual meteorological conditions prevailed, and a flight plan was not filed for the Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The local flight departed JAC at 1218. Several witnesses at JAC reported that the airplane departed runway 19, and immediately climbed to approximately 500 feet above ground level (agl), while maintaining runway heading. The airplane then turned left onto the crosswind leg of the traffic pattern and maintained a slight climb. Two witnesses, who were traveling southbound in motor vehicles on Highway 89 (parallel to JAC runway 01/19), reported that they observed the airplane on the left downwind leg at an altitude of 700 to 900 feet agl. One witness, who was also in a vehicle, observed the airplane in "normal flight" at an altitude of 800 to 1,000 feet flying parallel to the east of Highway 89. The witness observed the airplane turn left (west) onto the base leg for runway 19 "in normal flight and was descending but not what appeared to be abnormal." The airplane continued a nose-low descent toward the terrain. Approximately 200 feet agl, the airplane began a "steeper" nose-low descent toward terrain. The airplane then impacted terrain in a wings level attitude, bounced, nosed over, and came to rest inverted. During the descent, the witness did not noticed any movement of the elevator or other flight control surfaces, or any in-flight structural failure of the airplane. According to Federal Aviation Administration (FAA), the pilot was in communication with the JAC air traffic control tower during the accident flight. The pilot contacted the air traffic controller (ATC) and reported he wanted to depart JAC to the east with a left turn out. Shortly after departure, the pilot contacted ATC and stated he wanted to re-enter the traffic pattern and return to JAC for a full stop landing. The controller told the pilot to report left base for runway 19. The pilot reported left base for runway 19. No further communications were received by ATC from the pilot. During the communications, the pilot did not report any problems with the airplane. PERSONNEL INFORMATION The pilot, age 58, who was seated in the front seat position, held a commercial pilot certificate, issued February 25, 1970, with airplane multi-engine land, airplane single-engine land, and airplane instrument ratings. The pilot also held a type rating for Cessna CE-525S jet airplanes. The pilot was issued a third-class medical certificate on March 9, 2004, with the limitation, "Holder shall possess glasses that correct for near vision." The pilot's logbooks were not located; however, according to the pilot's March 9, 2004, medical certificate application, the pilot reported a total time of 9,400 hours, and 203 hours in the previous 6 months. AIRCRAFT INFORMATION The CGS Hawk Two Place Arrow was a high wing, 2-seat tandem airplane, constructed from aluminum tubing and Dacron covers, featuring dual 3-axis control. The orange and white accident airplane was configured with conventional fixed landing gear (a tricycle gear configuration was also available from the manufacturer). The wing (31 1/2-foot span, 147 square feet) consisted of one section per side with an aileron, 3-position flap, and aluminum wing strut. Each wing contained two 5-gallon fuel tanks, a total capacity of 20 gallons. The wings are attached to the fuselage, and a Velcro secured Dacron or Lexan "gap" cover completes the upper wing surface between the two wing sections and fuselage. The fuselage (cockpit) was an aluminum tubing construction covered with Dacron and a Lexan windscreen, which was sewn to the Dacron cover. The fuselage had four removable zipper doors which provide a full fuselage enclosure. The accident airplane was equipped with a heater which was mounted in the nose of the airplane. A single aluminum boom tube attached the fuselage and empennage. The empennage consisted of vertical and horizontal stabilizers, with rudder and elevator control surfaces. The accident airplane was originally equipped with an optional elevator trim tab. The flight control surfaces were operated via control cables. The dual stick controls were slaved via a torque tube. The torque tube assembly was routed inside the boom tube, and the rear stick was exposed through a rectangular cut-out in the top portion of the boom tube. The CGS Hawk Two Place Arrow was powered by a 100-horsepower, water-cooled, fuel-injected Hirth model 3701 engine, equipped with a three-blade IVOPROP electric in-flight adjustable, composite propeller. The engine was mounted at the rear of the fuselage, immediately aft of the wing. The accident airplane was built and completed in May 2005 by a CGS Aviation approved dealer located in West Virginia, in conjunction with partial assistance by the pilot. The airplane building records and logbooks were not obtained. According to the dealer and acquaintances of the pilot, the airplane had accumulated approximately 45 hours at the time of the accident. The accident airplane was eligible for certification in the experimental light-sport aircraft category. According to CFR Part 21.191(i)(1), after January 31, 2008, an experimental certificate would not be issued for the accident airplane. The airplane was not eligible for certification in the ultralight category due to a fuel capacity of greater than 10 gallons. According to the kit manufacturer and dealer, the pilot had intended on registering the airplane with the FAA; however, he had not completed the process at the time of the accident. METEOROLOGICAL INFORMATION At 1215, the JAC METAR (routine aviation weather report) reported the wind from 180 degrees at 4 knots, visibility 10 statute miles, sky clear, temperature 66 degrees Fahrenheit, dew point 41 degrees Fahrenheit, and an altimeter setting of 30.03 degrees inches of Mercury. AERODROME INFORMATION The Jackson Hole Airport, JAC, is a public, controlled airport located approximately 7 miles north of Jackson, Wyoming, at 43 degrees, 36.44 minutes north latitude, and 110 degrees, 44.265 minutes west longitude, at a surveyed elevation of 6,451 feet. The airport features one asphalt runway, Runway 1/19, which is 6,300 feet long and 150 feet wide. WRECKAGE AND IMPACT INFORMATION The accident site was located in sage brush-covered flat terrain approximately 575 feet west of Highway 89, and 3/4-mile north of the approach end of runway 19. Initial examination of the wreckage and accident site was completed by Grand Teton National Park personnel. With assistance from a local mechanic, the accident site was documented by the National Park Service on-scene coordinator. A global positioning system (GPS) receiver reported the location as 43 degrees 37.36 minutes north latitude and 110 degrees 43.38 minutes west longitude, at an elevation of 6,400 feet. The wreckage was distributed along a measured magnetic heading of approximately 320 degrees. The initial impact point was consistent with the fuselage and the main landing gear. The main wreckage came to rest inverted approximately 50 feet from the initial impact point. The main wreckage consisted of the left and right wings, boom tube, empennage, and fuselage tubing. The airplane wreckage was transported to a vacant hangar at JAC for further examination by the NTSB. On June 28, 2005, the wreckage was examined by the NTSB investigator-in-charge, two FAA inspectors, and the on-scene coordinator with the Grand Teton National Park. Examination of the wreckage revealed the left wing fabric was torn, the main spar intact, and the wing support structure was crushed aft. The forward and rear struts were fractured and remained attached to their respective wing and fuselage attach fittings. The left flap and aileron remained attached to the wing. Control continuity was established to the flap, and the aileron cable was separated and exhibited a random raveling of individual wires typical of an overload failure. The right wing fabric was torn, the main spar intact, and the wing support structure was crushed aft. The forward strut was intact, and the rear strut was fractured at its midpoint. The struts remained attached to their respective wing and fuselage attach fittings. The right flap and aileron remained attached to the wing. The right flap control tube was separated at the flap attach point, and the aileron cable was separated and exhibited a random raveling of individual wires typical of an overload failure. The boom tube was separated near the leading edge of the vertical stabilizer. The vertical and horizontal stabilizers were intact, and the elevator and rudder remained attached to the stabilizers. Elevator and rudder control continuity was established from the control surfaces to their respective cockpit controls. The elevator trim tab was not installed (According to friends of the pilot, the pilot removed the trim tab while transporting the airplane via truck after an incident in Nebraska). The fuselage was fragmented and destroyed. The front seat floor was crushed aft, and the rear seat floor had not been installed. The control stick assembly torque tube was fractured aft of the front control stick and forward of the aileron crank. The rear control stick was not installed. The front seat was bent and crushed, and the rear seat had not been installed. The front seat aluminum back displayed an impact mark consistent with the engine water pump. The instrument panel was bent and separated from the fuselage structure. The airspeed indicator needle displayed 120 knots, and the vertical speed indicator displayed greater than 1,500 feet per minute descent. The landing gear saddle and legs were separated from the boom tube. The fuselage covering and gap cover (located overhead between the wings) had not been installed. A Lexan windscreen, which was riveted onto the fuselage structure, was separated from the fuselage. The engine was separated from its mounting structure. The three-blade composite propeller was splintered and fragmented, and remained attached to the engine crankshaft. The propeller and crankshaft was manually rotated; continuity and thumb compression were established throughout the engine. PATHOLOGICAL INFORMATION An autopsy was performed on the pilot by Western Wyoming Pathology, Jackson, Wyoming, on June 28, 2005. Blood specimens for toxicological tests were taken from the pilot by the medical examiner. According to the autopsy, the cause of death for the pilot was blunt force trauma. The FAA's Bioaeronautical Sciences Research Lab, Oklahoma City, Oklahoma, examined the blood specimen taken by the medical examiner. Toxicological tests performed on the pilot were negative for all screened drugs and alcohol. Carbon monoxide and cyanide tests could not be performed. TEST AND RESEARCH A Garmin GPSmap 296 receiver, located at the accident site, was examined by the NTSB's Vehicle Recorders Laboratory in Washington, DC. Due to damage sustained during the impact sequence, the receiver was sent to the manufacturer for evaluation and data extraction. Data extracted from the unit included 12 individual trackpoints recorded on June 26, 2005, between 0607 and 1148. The locations of the trackpoints were within close proximity to JAC. No data was recorded on the day of the accident. On October 19, 2005, at the NTSB Materials Laboratory, Washington, DC, the forward portion of boom tube and enclosed controls, the front control stick assembly, the front bearing block with a portion of the fuselage, a damaged inspection mirror (found in the wreckage debris area), and an exemplar inspection mirror were examined. The examined portion of the boom tube was approximately 16 inches long and contained some of the elevator and aileron controls, and a reinforcing frame identified as an "H" member. The rear control stick protrudes out of a rectangular cutout on the upper surface of the boom tube and the aileron crank protrudes from the forward end of the boom tube. The front control stick is located forward of the front bulkhead. When the cockpit flight control components are properly assembled, the torque tube can only rotate in the front and rear bearing blocks as two locking collars, forward and rear, to prevent any longitudinal motion. The rear bearing block is bolted to the boom tube and the front bearing block is bolted to a fuselage tube. The front and rear control sticks are connected to the torque tube at pivot points, and cables attached to the front control stick are connected to the elevator control surface. The elevator tube connects the front and rear control sticks to each other so that forward and aft motion of either control stick controls the elevator. The aileron crank is bolted to the torque tube so lateral motion of either control stick rotates the torque tube, thereby moving the crank. The crank is connected to the ailerons by cables. Boom Tube The boom tube extends from slightly forward of the forward bulkhead to the empennage and is the main structural member of the aircraft. Examination of the boom tube revealed that two doublers and a reinforcing plate had been riveted to the tube. The first doubler and was wrapped around the boom tube and attached with 9 rivets. The second doubler was wrapped around the first doubler; started at the forward bulkhead and extended approximately 12 inches to the rear. A reinforcing plate, which also started at the forward bulkhead, extended 9 inches to the rear and wrapped around the second doubler. The second doubler was attached to the boom tube with 38 rivets, of which 19 were common to the reinforcing plate, and 4 were common to the internal "H" member. The "H" member consisted of two longitudinal tubes and two lateral tubes welded together to form an "H" shape. The "H" member was riveted into position, horizontally across the boom tube, to reinforce the boom tube at the landing gear saddle location. The "H" member, painted gray in color, was centered approximately 10 inches from the front bulkhead. According to a photograph provided by the accident airplane builder, the original "H" member was painted white, and the second doubler and reinforcing plate were not installed. The original "H" member was replaced during a repair, which was completed by the owner, after a hard landing incident (See Additional Information section of this report). The forward lateral tube of the "H" member had been deformed and bent to the rear and upwards. The plating at the lower portion of the rear control stick had been damaged, consistent with contact with the "H" member. An indentation was observed, and plating was missing, at the forward lower portion of the rear control stick, consistent with contact of these two areas together. Both sets of damage marks are consistent with the torque tube being moved to the rear. Examination of the rear edge of the rectangular cutout for the rear control stick revealed disturbed paint at three locations with no material deformation. The interior surface of the boom tube was examined and revealed a number of scratches that, in some case, had removed the paint to reveal bare material. One significant scratched area, was located above the "H" member. This area, was longitudinally oriented and accompanied by circumferential surface scratches that extended downward. A second significant area was located forward of the rear control stick and below the level of the "H" member. This area consisted of two longitudinally oriented surface scratches with circumferential surface scratches oriented downwards from the lower of the two longitudinal scratches. Before the removal of the control assembly from the boom tube, repeated att
The loss of airplane pitch control resulting from the pilot/owner's improper reinstallation of the rear locking collar on the elevator control torque tube, which allowed the torque tube to move rearward during flight and loosen the elevator control cable tension.
Source: NTSB Aviation Accident Database
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