Elk City, OK, USA
N7804C
Dahlman-Dower Tailwind W-8
The pilot’s in-flight weather briefing indicated that instrument meteorological conditions, including low ceilings, were forecast for the area. He then contacted the nearest Air Route Traffic Control Center and requested an instrument clearance to a nearby airport. The controller offered to vector the pilot for an instrument landing system, very-high frequency omnidirectional radio range, or area navigation/global positioning system approach to that airport, but the pilot said he was having gyro problems. The pilot said he would divert to a visual flight rules (VFR) airport. Radio and radar contacts were then lost. A postaccident examination of the wreckage at the scene indicated that the airplane struck the shoulder of a road in an inverted, nose-down attitude. The only navigational charts found at the accident scene were a bound VFR chart atlas. No instrument flight rules charts were found. A further examination of the airplane showed that the airplane was equipped with basic VFR instrumentation only. Analysis of radar data revealed that the airplane made three turns: two tight left turns followed by a wide right turn. These turns took place in the last few minutes of flight and were consistent with a spiraling descent.
HISTORY OF FLIGHT On April 21, 2011, approximately 1129 central daylight time, a Dahlman-Dower Tailwind W-8, N7804C, registered to and operated by the pilot, was substantially damaged when it impacted terrain approximately 9 miles northwest of Elk City, Oklahoma. Instrument meteorological conditions (IMC) prevailed at the time of the accident. The personal flight was being conducted under the provisions of 14 Code of Federal Regulations (CFR) Part 91, and an instrument flight rules (IFR) clearance had been issued by Fort Worth Air Route Traffic Control Center (FTW ARTCC). The pilot, the sole occupant on board, was fatally injured. The cross-country flight originated at Pueblo (PUB), Colorado, at 0756 mountain daylight time. At the time of the accident, the pilot was attempting to divert to Liberal (LBL), Kansas. The pilot was in the process of delivering the airplane to perspective purchasers in McKinney (T31), Texas. He departed Hailey, Idaho, on April 19, and flew to PUB, where he stayed with family for two days. He departed PUB April 21. According to Federal Aviation Administration (FAA) records, between 1036 and 1100 the pilot had attempted to contact Mc Alester Flight Watch on frequency 122.6 at 1036, but without success. Kansas City Flight Watch heard the pilot calling and established radio contact with him at 1100. The pilot reported he was 30 miles northeast of Sayre (SYO) VOR (Very High Frequency Omnidirectional Radio Range) at 8,500 feet, and requested the SYO weather and a frequency for the Fort Worth Air Route Traffic Control Center (FTW ARTCC). The briefer advised that the nearest weather reporting station to SYO was Clinton-Sherman Airport (CSM), which was reporting the wind to be from 120 degrees at 9 knots; visibility, 10 miles; ceiling, 1,000 feet overcast; temperature, 12 degrees C. (Celsius); dew point, 8 degrees C.; altimeter, 30.02 inches of mercury. The briefer also advised the pilot that IFR and low ceilings were forecast for the Fort Worth area, and VFR flight was not recommended in southwestern Oklahoma. The briefing ended at 1104. At 1108, the pilot contacted FTW ARTCC and advised he was 20 miles northwest of Sayre and requested an IFR clearance to CSM. The controller cleared the pilot to CSM via direct routing and also cleared him to descend, at the pilot's discretion, from 8,500 to 5,000 feet. The pilot asked the controller if he had any ceiling reports. The controller advised that a Bonanza 10 miles south of his position was at 6,000 feet and in the clouds, and another aircraft had made an instrument approach to Weatherford, Oklahoma (30 miles northeast of his position) and had broken out at 1,400 feet. The pilot replied that he wanted to remain at 8,500 feet for a little while longer. The controller then gave the pilot the CSM 1053 weather observation (see above). At 1111, the controller asked the pilot if he wanted the ILS (instrument landing system) approach to CSM, or a different approach. The pilot replied he wanted to go direct to SYO, and then direct to CSM. The controller offered to vector the pilot for an ILS, VOR, or RNAV/GPS approach. The pilot said he was having "a little gyro problem here." The controller told the pilot to fly a heading of 065 degrees. At 1117, the pilot said he was ready to descend and he was cleared to descend to 5,000 feet at pilot's discretion. When queried by the controller, the pilot said he had "no gyros" and would be unable to execute the ILS approach. The controller told him that Amarillo, Texas, which was behind him and 110 miles away, was reporting slightly better VFR weather. He was told the minimum en route altitude along his route of flight was 4,500 feet, and he was instructed to maintain 5,000 feet. Shortly thereafter, the controller cleared the pilot to climb and maintain 8,000 feet to get above the clouds, and the pilot acknowledged the clearance. At 1123, the controller advised the pilot that Liberal, Kansas, was reporting VFR conditions and scattered clouds at 3,900 feet. The pilot said he would divert to Liberal. He was told that Liberal was 115 miles ahead and to fly a heading of 312 degrees. The pilot replied he was still trying to get on top and when asked his altitude, he replied he was at 5,400 feet. He was again instructed to climb and maintain 8,000 feet and the pilot acknowledged at 1127. This was the last radio transmission from the pilot. Radar contact was lost at 1129. At 1225, FTW ARTCC issued an ALNOT (alert notice) for the missing airplane, and search and rescue was notified. The owner of the property on which the airplane crashed happened upon the wreckage and notified the Beckham County Sheriff, who in turn notified FTW ARTCC at 1308. There were no witnesses to the accident. PERSONNEL (CREW) INFORMATION The pilot, age 63, held a commercial pilot certificate, dated March 17, 2010, with airplane single/multiengine land and instrument ratings. He also held a flight instructor certificate, dated October 23, 2010, with airplane single/multiengine and instrument ratings. The pilot held a mechanic's certificate, dated September 7, 2006, with airframe and powerplant (A&P) ratings, and a repairman's certificate, dated November 30, 1992. His second class airman medical certificate, dated April 5, 2011, contained the restriction, "Must wear corrective lenses." When the pilot applied for his most recent medical certification, he estimated his total flight time at 10,000 hours. The pilot had been a flight instructor for 33 years. He flew for Mountain Canyon Flying in McCall, Idaho, where he instructed pilots in the fundamentals of backcountry flying. AIRCRAFT INFORMATION N7804C (serial number DD1), a Tailwind W-8, was an amateur-built airplane certificated by the FAA in the experimental category. It was designed by Sylvester J. "Steve" Whitman and manufactured by Dahlman and Dower. It was a high wing, braced cabin monoplane with a conventional landing gear. It had a steel tubing fuselage, wood wings, and fabric covering. N7804C was equipped with a Lycoming O-290-G engine (serial number 985-24), rated at 125 horsepower, and driving a Sensenich 2-blade, all wood, fixed pitch (66 x 74) propeller (serial number 791). The propeller was installed on the airplane on March 10, 2010. Documents found in the wreckage indicated the airplane had a gross weight of 1,400 pounds, an empty weight of 900 pounds, and had a fuel capacity of 25 gallons. According to the maintenance records, the last conditional inspection was performed on April 1, 2011, at a tachometer time of 152.2 hours. At that time, the airframe had accrued 1,113.1 hours, and engine had accrued 878.5 hours and 484.7 hours since major overhaul. METEOROLOGICAL INFORMATION When N7804C departed PUB at 0756, VMC prevailed and the following METAR (Aviation Routine Weather Report) was observed: KPUB 211253Z: Wind, calm; visibility, 10 statute miles; temperature, 1 degree Celsius (C ); dew point, -3 C.; altimeter, 29.82 inches of Mercury. At the time of the accident, the following METARs were recorded at Clinton-Sherman Airport, located approximately 20 miles southeast, at 1053 and 1153: KCSM 211653Z: Wind, 160 degrees at 9 knots; visibility, 4 statute miles, mist; ceiling, 1,000 feet overcast; temperature, 11 degrees C.; dew point, 09 degrees C.; altimeter 30.01 inches of Mercury; Remarks, precipitation discriminator; ceiling, 800 feet variable 1,000 feet. KCSM 211753Z: Wind, 170 degrees at 10K knots; visibility, 8 statute miles; ceiling, 1,000 feet overcast; temperature, 13 degrees C.; dew point, 9 degrees C.; altimeter, 29.97 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The on-scene accident investigation was conducted on April 22, 2011. The accident site was located on North 1980 Road (Randall Avenue), about 2 miles north of East 1016 Road, and about 10 miles north-northwest of Elk City, Oklahoma, in Beckham County. The on-scene investigation disclosed the airplane had struck the shoulder of North 1980 Road in an inverted, nose-down attitude. There was a crater on the shoulder of the road, containing the propeller. The crater measured 7 feet x 4 feet x 1 foot. All six propeller mounting bolts were sheared off the crankshaft and were in the propeller flange. The propeller exhibited "S" bending and there were 90-degree scratch marks on the cambered surfaces. There was a scrape mark on the asphalt pavement, consistent with a left wing strike. Remnants of the left and right ailerons and control rods lay 60 and 200 feet beyond the crater alongside the road, respectively. The empennage was against a barbed wire fence atop an embankment, 115 feet beyond the engine crater and on a magnetic heading of 349 degrees. The fuselage and cabin sat upright and about 6 feet beyond the empennage on the other side of the fence. In front of the fuselage was the instrument panel. No gyroscopic instruments were seen or found. The inverted engine was 30 feet beyond and on a magnetic heading of 350 degrees. The power quadrant was nearby. The air scoop made up the bottom potion of the engine cowling. It was found 70 feet to the left of the engine and exhibited no crushing damage. Loose papers were collected and examined. The only navigational charts found were a bound VFR chart atlas. No IFR charts were found. In addition, pre-accident photographs of the airplane revealed it was equipped with basic VFR instrumentation only. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was conducted by the Oklahoma Medical Examiner's Office. According to the autopsy report, the cause of death was multiple blunt force trauma. The manner of death was accident. FAA’s Civil Aeromedical Institute’s (CAMI) toxicology report indicated no drugs were detected in the liver. Carbon monoxide and cyanides tests were not performed. Ethanol, methanol, butanol, and propanol were detected in various tissue samples, but the report noted putrefaction of the samples. TESTS AND RESEARCH National Track Analysis Program (NTAP) data was obtained from the FTW ARTCC and given to the Denver ARTCC Quality Assurance office for download and readout. Several plots were generated and overlaid on a satellite photograph. Plots on NTAP Map 1 began at 1009:20, when the airplane was at 8,600 feet, and continued to 1021:46, when the airplane had descended to 5,000 feet. During this time, the transponder was squawking 0524 and the pilot had been instructed to fly a heading of 065 degrees and to descend and maintain 5,000 feet. Plots on NTAP Map 3 began at 1018:46, when the airplane was at 8,000 feet, and continued to 1028:12 when the transponder's Mode C was indicating 0 feet (the last 14 radar sweeps indicated 0 feet). FAA's Advisory Circular (AC) 60-4A, entitled "Pilot's Spatial Disorientation," states (in part): "The attitude of an aircraft is generally determined by reference to the natural horizon or other visual references with the surface. If neither horizon nor surface references exist, the attitude of an aircraft must be determined by artificial means from the flight instruments. Sight, supported by other senses, allows the pilot to maintain orientation. However, during periods of low visibility, the supporting senses sometimes conflict with what is seen. When this happens, a pilot is particularly vulnerable to disorientation. The degree of disorientation may vary considerably with individual pilots. Spatial disorientation to a pilot means simply the inability to tell which way is 'up.' "The disoriented pilot may place the aircraft in a dangerous attitude..."
The pilot's decision to attempt flight into instrument meteorological conditions in an airplane that was equipped for flight in visual meteorological conditions only, which resulted in the pilot’s spatial disoriented and loss of control of the airplane.
Source: NTSB Aviation Accident Database
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