History of Flight
On April 21, 2011, at approximately 1129 central daylight time, a Dahlman-Dower Tailwind W-8, registration N7804C, was substantially damaged when it impacted terrain about 9 miles northwest of Elk City, Oklahoma. Instrument meteorological conditions (IMC) prevailed at the time. The flight was conducted under 14 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, was fatally injured. The cross-country flight originated at Pueblo, Colorado (PUB), at 0756 mountain daylight time, and was en route to McKinney, Texas (T31), where the airplane was to be delivered to prospective purchasers. At the time of the accident, the pilot was attempting to divert to Liberal, Kansas (LBL).
According to FAA records, the pilot contacted Kansas City Flight Watch at 1100, requesting weather and a frequency for FTW ARTCC. The briefer provided the Clinton-Sherman Airport (CSM) weather and advised that IFR and low ceilings were forecast for the Fort Worth area, and VFR flight was not recommended in southwestern Oklahoma. At 1108, the pilot contacted FTW ARTCC, requested an IFR clearance to CSM, and was cleared to CSM via direct routing and to descend at his discretion from 8,500 to 5,000 feet. The pilot asked for ceiling reports; the controller reported that a Bonanza 10 miles south was at 6,000 feet and in clouds, and another aircraft had broken out at 1,400 feet near Weatherford. The pilot indicated he wanted to remain at 8,500 feet.
At 1111, the controller offered vectoring for an approach. The pilot replied he wanted to go direct to Sayre (SYO) then CSM, and mentioned having “a little gyro problem.” He was told to fly a heading of 065 degrees. At 1117, the pilot said he was ready to descend and was cleared to 5,000 feet. When queried, he said he had “no gyros” and could not execute an ILS approach. The controller advised that Amarillo, Texas, was reporting better VFR weather and that the minimum en route altitude was 4,500 feet; he instructed the pilot to maintain 5,000 feet. Shortly after, the controller cleared the pilot to climb to 8,000 feet to get above clouds.
At 1123, the controller advised that Liberal, Kansas, was VFR with scattered clouds at 3,900 feet. The pilot said he would divert to Liberal. He was told to fly a heading of 312 degrees. The pilot replied he was still trying to get on top and reported his altitude as 5,400 feet. He was again instructed to climb to 8,000 feet and acknowledged at 1127. This was the last transmission. Radar contact was lost at 1129. An ALNOT was issued at 1225, and the wreckage was discovered by a property owner, who notified the Beckham County Sheriff at 1308. There were no witnesses.
Personnel Information
The pilot, age 63, held a commercial pilot certificate with airplane single/multiengine land and instrument ratings, and a flight instructor certificate with the same ratings. He also held an airframe and powerplant mechanic certificate and a repairman certificate. His second-class medical certificate, dated April 5, 2011, required corrective lenses. He estimated total flight time at 10,000 hours and had been a flight instructor for 33 years.
Aircraft Information
N7804C (serial number DD1) was an amateur-built Tailwind W-8, a high-wing, braced cabin monoplane with conventional landing gear, steel tubing fuselage, wood wings, and fabric covering. It was powered by a Lycoming O-290-G engine rated at 125 horsepower, driving a Sensenich two-blade wooden fixed-pitch propeller. The airplane had a gross weight of 1,400 pounds, empty weight of 900 pounds, and fuel capacity of 25 gallons. The last conditional inspection was performed on April 1, 2011, at a tachometer time of 152.2 hours; the airframe had 1,113.1 hours and the engine had 878.5 hours (484.7 hours since major overhaul).
Meteorological Information
At departure from Pueblo at 0756, VMC prevailed: wind calm, visibility 10 miles, temperature 1°C, dew point -3°C, altimeter 29.82 inHg. At the accident time, Clinton-Sherman Airport (20 miles southeast) reported at 1053: wind 160° at 9 knots, visibility 4 miles in mist, ceiling 1,000 feet overcast, temperature 11°C, dew point 9°C, altimeter 30.01 inHg; and at 1153: wind 170° at 10 knots, visibility 8 miles, ceiling 1,000 feet overcast, temperature 13°C, dew point 9°C, altimeter 29.97 inHg.
Wreckage and Impact
The accident site was on North 1980 Road, about 2 miles north of East 1016 Road, 10 miles north-northwest of Elk City, Oklahoma. The airplane struck the road shoulder in an inverted, nose-down attitude, leaving a crater 7x4x1 foot containing the propeller. All six propeller mounting bolts were sheared. The propeller showed S-bending and 90-degree scratch marks. A scrape mark on the asphalt was consistent with a left wing strike. Aileron remnants lay 60 and 200 feet beyond the crater. The empennage was against a fence 115 feet beyond the crater on a magnetic heading of 349°, and the fuselage and cabin were 6 feet beyond the fence. The instrument panel lay in front of the fuselage; no gyroscopic instruments were observed. The inverted engine was 30 feet beyond on heading 350°. The air scoop was found 70 feet to the left of the engine with no crushing damage. Loose papers included a bound VFR chart atlas; no IFR charts were found. Pre-accident photos showed the airplane had basic VFR instrumentation only.
Medical and Pathological Information
An autopsy by the Oklahoma Medical Examiner’s Office listed the cause of death as multiple blunt force trauma, manner of death accident. FAA’s CAMI toxicology detected no drugs in the liver; ethanol, methanol, butanol, and propanol were found in various tissue samples, but the report noted putrefaction. Carbon monoxide and cyanides tests were not performed.
Tests and Research
Radar data from FTW ARTCC showed plots from 1009:20 (8,600 ft) to 1021:46 (5,000 ft) with transponder squawking 0524, and from 1018:46 (8,000 ft) to 1028:12 (Mode C indicating 0 ft for the last 14 sweeps). FAA Advisory Circular 60-4A on spatial disorientation was referenced in the investigation, noting that during low visibility, supporting senses may conflict with visual cues, making a pilot vulnerable to disorientation.