History of Flight
On October 9, 2015, about 1919 eastern daylight time, a Columbia Aircraft Manufacturing LC41-550FG, N1058S, impacted the ground in an uncontrolled descent after encountering a thunderstorm near Erwin, Tennessee. The private pilot and the passenger were fatally injured, and the airplane was destroyed. The airplane was owned and operated by the pilot. The personal flight was conducted under 14 Code of Federal Regulations Part 91. The flight originated from Tyson Airport (TYS) in Knoxville, Tennessee, about 1830, with an intended destination of Monroe County Airport (BMG) in Bloomington, Indiana. Night visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed.
The flight had originated earlier in the day from Kissimmee Gateway Airport (ISM) in Orlando, Florida. Prior to departing ISM, the pilot's login credentials were used to access weather information via DUAT, which included forecasts predicting showers and thunderstorms in the TYS area and north beginning about 1700, as well as a "Severe Weather Outlook" noting a marginal risk of severe thunderstorms.
While en route, the pilot diverted to TYS to "check the weather," landing about 1745. At about 1750, his credentials were used again to obtain a weather briefing. About 1830, the airplane departed TYS and climbed to 15,000 ft msl on an easterly heading, paralleling a line of convective weather to the north. The pilot was in communication with air traffic control (ATC).
Between 1836 and 1854, the controller provided deviation clearances, and the pilot acknowledged having NEXRAD on board. At 1911, the pilot requested and received clearance to turn left. At 1913, he was cleared to climb from 15,000 to 17,000 ft msl. The last recorded transmission from the accident flight was at 1918:29. Radar data then showed the airplane descending from about 17,500 ft to ground level in approximately one minute. Multiple witnesses observed the airplane descending, turning right, and exploding on impact; one reported heavy rain at the time.
Personnel Information
According to FAA records, the pilot, age 45, held a private pilot certificate with airplane single-engine land and instrument ratings, issued December 28, 2013. He held a third-class medical certificate issued April 18, 2014, with a limitation to wear corrective lenses. At the medical examination, he reported 279 total flight hours, with 73.9 in the previous 6 months.
Aircraft Information
The airplane, N1058S, was issued an airworthiness certificate in 2007 and registered to the pilot in January 2015. The most recent annual inspection was on April 15, 2015, at 1,098.7 total flight hours. Subsequent maintenance was recorded on June 24, 2015, at 1,113.1 hours. The engine, a Continental Motors TSIO-550-C20B, had 37.5 hours since major overhaul at the last annual inspection. The airplane was not equipped with onboard weather radar but could receive XM Satellite Weather via a Garmin G1000 avionics suite. The pilot had an active subscription for Aviator Pro weather services.
Meteorological Information
A special weather observation at Tri-Cities Regional Airport (TRI) at 1937 reported thunderstorms and rain, visibility 6 miles, scattered cumulonimbus at 2,300 ft, broken at 6,000 ft, overcast at 11,000 ft. The thunderstorm began at 1931 with frequent lightning. At Elizabethton Airport (0A9), the 1915 observation showed 10 miles visibility, few clouds at 6,000 ft, scattered at 7,500 ft, broken at 9,000 ft.
Weather radar data showed a line of convective cells with reflectivity greater than 55 dBZ near the accident location. At 1855, a convective SIGMET was issued for a line of thunderstorms 50 miles wide moving from 260° at 30 knots, with cloud tops to FL440. Lightning data from 1900 onward showed no lightning associated with the cell coinciding with the airplane's location at the time of the accident. Satellite data indicated cloud-top temperatures between -20°C and -53°C, corresponding to heights of 22,600 ft msl to above 35,000 ft msl. Civil twilight ended at 1923; the moon had set earlier.
Wreckage and Impact Information
The wreckage was found in the Cherokee National Forest at an elevation of 2,825 ft msl. The airplane impacted two 27-ft-tall trees. The debris path was compact, with an impact crater about the length of the airplane's wingspan. The airframe was impact-damaged, segmented, and thermally destroyed. The engine was in a 4-ft-deep crater, still attached to the firewall. The propeller was separated at the crankshaft flange. The attitude indicator displayed a nose-down, inverted right-wing-low attitude. Left and right wings were thermally destroyed; speed brakes were stowed. The empennage was thermally damaged. The engine showed torsional twist and radial cracking on the crankshaft. The propeller blades exhibited leading edge gouging, aft bending, and forward bending on two blades, consistent with power at impact.
Medical and Pathological Information
An autopsy performed on the pilot listed cause of death as multiple blunt force injuries. Toxicological testing on muscle tissue detected 0.01 g/dl of ethanol, as well as citalopram and its metabolite. The FAA noted that ethanol may also be produced postmortem. Citalopram is an antidepressant; the pilot's medical records indicated his depression had improved significantly on the medication.
Additional Information
The FAA publication "General Aviation Pilot's Guide to Preflight Weather Planning" advises that datalink weather is intended for strategic decisions only and should not be used for tactical navigation through thunderstorms. The FAA's Pilot Handbook warns that aircraft entering thunderstorms can experience updrafts and downdrafts exceeding 3,000 ft per minute and recommends circumnavigating by at least 5 nautical miles.