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On March 15, 1995, about 1406 mountain standard time, a home built BD5TP, N777TK, impacted in a field under unknown circumstances approximately four miles east of Byers, Colorado. The pilot sustained fatal injuries and the aircraft was destroyed by impact and postimpact fire. No flight plan was filed for this local area personal flight which originated from Front Range Airport, Watkins, Colorado, about 1215. Visual meteorological conditions prevailed.
According to available information gathered from relatives, the builder, the FAA, and persons at Front Range Airport, the pilot purchased the aircraft on February 21, 1995, from the builder and transported it by surface transportation from Scottsdale, Arizona, to Front Range Airport. At that time, an operating limitations document was in effect having been issued by the FAA Scottsdale Flight Standards District Office on May 16, 1994. The pilot made some modifications, including the installation of the remaining portions of a variable pitch propeller system, and conducted a taxi test on March 8, 1995. A second taxi test was conducted on March 9, 1995. During the second taxi test, the propeller inadvertently struck the ground damaging the tips of the two-bladed wooden propeller. The owner removed the propeller, repaired the tip damage, and reinstalled the propeller on the aircraft. The details of repair and rebalancing are unknown.
On March 10, 1995, an FAA designated airworthiness representative (DAR) issued a revised Amateur Built Phase 1 operating limitations document applicable to N777TK. A copy of the document is attached and limited the pilot to operate in a designated test area and restricted him from acrobatic maneuvers for a period of 15 flight hours. A statement by the DAR is also attached.
During a third planned taxi test on March 13, 1995, the aircraft inadvertently became airborne, and the pilot spent approximately one hour in the pattern with the landing gear down and the flaps set at 20 degrees.
On March 14, 1995, the pilot flew the first planned test flight for a duration of eight tenths of an hour. During this flight, on which the pilot remained in the pattern, the gear and flaps were retracted and a low pass (reported as 20 to 50 feet) down the runway was conducted at a reported airspeed of 170 mph. On March 15, 1995, a second test flight was conducted. About 1450, a rancher near Byers, went to a pasture to feed cattle and found the burned out remains of the aircraft, still smoldering. The pilot had apparently been ejected during impact and his body was located in the wreckage scatter pattern. The time of the accident is estimated to be at 1406 due to the pilot's watch having stopped at that time.
According to a witness who was located at Buckley Air National Guard Base northwest of Front Range Airport, between 1300 and 1330, he observed an aircraft, matching the description of the accident aircraft, doing what appeared to be wingover type maneuvers to the northeast of the base. (The Air Guard Base is located approximately 30 miles west of the accident site.) PERSONNEL INFORMATION
According to FAA records, the pilot received his private pilot certificate on December 14, 1994, with a single engine land rating. At the time of the accident, he had accumulated approximately 113 hours flight time. According to available information gathered from all sources, the pilot's flight time prior to purchasing the accident aircraft was in Cessna 150 and 172 aircraft. He had no instrument training or certificate, no acrobatic training or experience, and his night and instrument time are unknown.
Generically, this aircraft was designed as a high performance, single place, low wing, all-metal, pusher configuration, day VFR, sport aircraft. It had a wing span of 19.5 feet, length of 13.3 feet, and a height of 4.2 feet. Loading was designed to 6.5 positive and 3 negative g's and the aircraft had limited acrobatic capability. The flight control system was manual and incorporated side stick cockpit control. Trim tabs were installed on all flight control surfaces. Manually operated plain flaps extended from the wing root to the inboard end of the ailerons. Two flap down positions were available: a takeoff position of 20 degrees, and a landing position of 40 degrees.
The landing gear was tricycle and fully retractable by a manual system. The nose gear was free castoring with a centering mechanism and ground steering was accomplished through differential braking from the hydraulic main landing gear brakes.
Fuel capacity was 29 gallons with 28 gallons available from two wing tanks selectable from a left-right-off valve in the cockpit.
Fuel quantity gauges were of the fiber optic type. Maximum endurance was approximately 2.5 hours with the power plant used in this application.
The engine was a single stage centrifugal compressor, annular cumbustor single stage turbine, originally designed for use as an auxiliary power plant for the Boeing Vertol CH47 helicopter. It was built by the SOLAR Engine Division, International Harvester, which was later sold to Sunstrand. According to Sunstrand, this type engine was neither designed nor intended for service as an aircraft primary power plant and they feel the user may be exposed to imminent danger and risk of serious injury or death if the engine is used as an aircraft power plant.
In this application, the engine and accessories weighed approximately 76 pounds and turned at a normal operating speed of 56,000 rpm with a top speed of 64,000 rpm. Through internal planetary gearing, the output shaft turned at 6,000 rpm and at 56,000 rpm engine operating speed produced approximately 90 shaft horsepower. Drive speed to the propeller was further reduced through a differential pulley and belt drive assembly so that the propeller turned at approximately 3,000 rpm. Fuel burn rate in the original design application ranged from 7.3 gallons per hour to 12.5 gallons per hour.
The propeller was a two-bladed 46 inch wooden variable pitch design manufactured by VARI-PROP, Exeter, England. The system functioned by displacement of hydraulic fluid through operation of a manual cockpit propeller controller which forced fluid into the pitch operating mechanism in the propeller hub. The system was independent of all other aircraft systems and adjustable through a 70 degree angle.
The nearest weather reporting facility to the accident site was Denver International Airport which was located approximately 30 miles to the northwest. Weather at that facility at the time of the accident is recorded under weather information in this document. According to the rancher who discovered the aircraft, skies were clear and the wind was from the southeast at about 40 miles per hour with some heavier gusts.
WRECKAGE AND IMPACT INFORMATION
The accident site was flat pasture land with an average upslope of 3 degrees to the northwest. Vegetation was primarily low field grass, yucca, and cactus.
The primary impact crater was approximately 3 by 3 feet, with an average depth of about 8 inches. Pieces of the wooden propeller blades were found in and around this gouge. Ground scarring was present from the gouge extending 48 feet on a base track of 305 degrees magnetic to the main wreckage which was oriented on a heading of 360 degrees. A fire pattern extended from the main wreckage for about 18 feet oriented on a track of 340 degrees with a width extending to 15 feet. The propeller hub was found 30 feet and 70 degrees to the right of the gouge/track.
Wreckage scatter extended from the fire pattern for a maximum of 80 feet oriented to the north and northwest. The scattered wreckage consisted of plexiglass and miscellaneous interior parts of the cockpit area.
The nose section and cockpit area were not discernable and appeared to have been consumed by fire from the nose extending rearward to the engine, which was installed aft of the cockpit. The 5 point restraint system buckles were found in the wreckage and were in the clasped position. The belts were consumed by fire.
The wings remained properly oriented to the fuselage and the wing root area was destroyed by fire. The outer wings were intact and exhibited uniform chordwise wrinkling of the upper skin extending from the tips inboard. Flap position could not be determined and the landing gear was found in the retracted position.
Fuel tank integrity was compromised and no fuel was found in either tank. The smell of jet fuel was present throughout the accident site.
The engine sustained superficial fire damage and remained attached in its normal mounting area. The accessory section, consisting of the starter, alternator, fuel pump, and fuel control separated from the engine and were found, as a unit, on the left side of the aircraft next to the engine. The power transmission shaft separated from the engine and was found in the burn area. The lower power transfer pulley was attached to the shaft but partially melted.
The empennage area consisting of the horizontal stabilizers, vertical stabilizer, upper power transmission shaft, sprague clutch, and associated framing and skin was intact and except for the upper pulley, outside the fire area. The clutch functioned normally and the shaft turned freely though it had been displaced rearward approximately 14 inches from its normal position. The exit point of the power shaft at the propeller attach point was sheared and exhibited twisting at the shear surface.
MEDICAL AND PATHOLOGICAL INFORMATION
An autopsy was performed by the Arapahoe County Medical Examiner. Extensive spinal compression damage was noted.
TESTS AND RESEARCH
The engine was examined at the facilities of Beegles Aircraft Services, Greeley, Colorado. The examination provided no evidence that the engine had sustained preimpact damage. Engine operation at the time of the accident could not be determined.
The wreckage was released to the custody of Beegles Aircraft Services on March 28, 1995. No parts were retained.