History of Flight
On December 3, 2011, about 1335 mountain standard time, a Socata TB21 airplane, N25153, collided with terrain near Silverton, Colorado. The private pilot and three passengers were fatally injured. The airplane was operated under Part 91 as a personal flight. Instrument meteorological conditions (IMC) prevailed, and no flight plan was filed for the cross-country flight. The flight departed Animas Air Park Airport (00C), Durango, Colorado, at 1319, en route to Aspen-Pitkin County Airport (ASE), Colorado.
A review of air traffic control (ATC) recordings showed the pilot contacted ATC at flight level 200 (about 20,000 feet) and 12 miles southeast of Telluride, Colorado. He requested VFR flight following to ASE and reported he could not descend below his altitude and maintain VFR. Shortly after, the airplane disappeared from radar and contact was lost. No distress calls were reported.
Several people in and near Silverton reported hearing the airplane, but no one saw it before impact. Witnesses described snowing weather with poor visibility. One witness, cross-country skiing, heard the airplane directly above him, sounding like aerobatics or tricks, as if the pilot had difficulty navigating. Another witness, about a mile from the crash site, heard the airplane racing down and then back up rapidly, with varying engine volume, as if changing elevation quickly. The NTSB IIC asked if she had heard aerobatics before; she said yes, on TV, and that was what it sounded like.
Pilot Information
The pilot, age 59, held a private pilot certificate for airplane single-engine land and a third-class medical issued October 4, 2011, with a restriction for glasses for near vision. His logbook showed 593.5 total hours, with 217.4 hours in the accident airplane. He was not instrument rated and had logged only 4.4 hours of simulated instrument time, the last on August 21, 2001. No recent instrument flight training was recorded. His last flight review was on July 11, 2011, in the accident airplane.
Aircraft Information
The accident airplane was a Socata TB21, a low-wing, four-place airplane with retractable gear, powered by a 250-horsepower, turbocharged, fuel-injected Lycoming TIO-540-AB1AD engine driving a three-bladed constant-speed Hartzell HC-C3YR-1RF propeller. Maintenance records were not recovered; the date of the last annual inspection is unknown. Based on a logbook comment, the airplane had at least 2,120 hours prior to the accident.
Meteorological Information
An NTSB meteorologist conducted a weather study. A surface trough and low pressure system near the accident site produced clouds and precipitation. Converging surface winds lifted existing clouds, and a mid-level trough moving east through the flight path was expected to produce clouds and precipitation in the mountain terrain. Satellite data showed cloud tops increasing from 13,000 feet msl at 1200 MST to between 19,000 and 22,000 feet msl at 1400 MST. Radar from Grand Junction, Colorado, recorded light precipitation echoes near the site. AIRMETs issued before departure advised of moderate turbulence, moderate icing, IFR conditions with precipitation and mist, and mountain obscuration due to clouds, precipitation, and mist. Witnesses reported low clouds and light snow. At 1335, an automated station at Telluride Regional Airport (KTEX), about 13 miles northwest, reported wind from 230 degrees at 4 knots, visibility 10 statute miles, scattered clouds at 1,900 feet, broken at 3,700 feet, overcast at 6,000 feet, temperature 27°F, dew point 21°F, and barometric pressure 29.82 inHg.
Communications
The pilot contacted Denver Center, requesting VFR flight following to Aspen, and reported about 12 nautical miles southeast of Telluride. Denver Center confirmed he was at 20,000 feet and reminded him that VFR requires being below flight levels. The pilot said he would descend as soon as possible. When asked if he could maintain VFR below his altitude, he said he could not. Asked if he was capable of IFR flight, he replied, “I’m capable. I’m studying it at this time, but if you could help me head on over, I’d sure appreciate it.” Asked if he was qualified, he said he was not. That was the last communication.
Wreckage and Impact
The wreckage came to rest in snow-covered mountainous terrain with tall pine trees. The debris field began with the right wing and continued about 1,200 feet down the mountain slope on a magnetic heading of 065 degrees, at elevations between 10,400 and 9,750 feet msl. Wreckage distribution and tree damage were consistent with an inflight breakup. Terrain, snow, and weather prevented a thorough on-scene examination; a follow-up was conducted after recovery.
An examination by the NTSB IIC and a technical advisor from the airframe manufacturer found flight controls fractured in multiple locations; when reconstructed, they appeared continuous prior to the accident, with overload fractures. The left wing bent upward from the root to near one-third span, then downward, with 45-degree creasing near the root. The right wing was fractured and separated just outboard of the wing spar doubler; the top of the spar I-beam was twisted forward and compressed downward. The right wing showed upward bending, and the right flap bent upward near mid-span. When reconstructed, the right wing had displaced upward over 80 degrees. The empennage showed creasing near the aft cabin and middle; skin and pop-rivets showed tearing and buckling downward. Cockpit instruments: the turn indicator showed inverted, altimeter Kollsman windows set to 29.92, attitude indicator showed inverted with approximately 190 degrees right roll and 45 degrees nose down; its gyro had rotational scoring. The vacuum pump also had rotational scoring. The propeller blades (A, B, C) were examined: Blades A and B were heavily damaged compared to blade C, which was relatively undamaged. Blade A had S-bending, leading edge polishing, gouges, and chord-wise scratches. Blade B had fractured from the hub with similar marks. Blade C was relatively undamaged.
The engine was examined by the NTSB IIC and a technical advisor from the engine manufacturer. Damage prevented a compression check, but manual rotation of the propeller established continuity from the crankshaft to the hydraulic lifts, and cylinder rocker arms operated normally. No anomalies were detected.
Medical and Pathological Information
An autopsy performed on the pilot by the Colorado District 21 medical examiner ruled the cause of death as blunt trauma and the manner as accident. Forensic toxicology on pilot and passenger specimens by the FAA laboratory did not find ethanol or drugs in the pilot; carbon monoxide and cyanide tests were not suitable for the pilot. Passenger specimens did not detect carbon monoxide or cyanide.
Additional Information
An excerpt from the FAA’s Airplane Flying Handbook (8083-3) concerning inadvertent VFR flight into IMC states: “Accident statistics show that the pilot who has not been trained in attitude instrument flying, or one whose instrument skills have eroded, will lose control of the airplane in about 10 minutes once forced to rely solely on instrument reference.” And “If the natural horizon were to suddenly disappear, the untrained instrument pilot would be subject to vertigo, spatial disorientation, and inevitable control loss.”
A previous NTSB recommendation (A-05-025, 2005) to the FAA proposed that for pilots without recurrent instrument training, the biennial flight review include demonstration of control and maneuvering solely by reference to instruments, including straight and level flight, constant airspeed climbs and descents, turns to a heading, and recovery from unusual attitudes. The recommendation status is “open-unacceptable response.”