History of Flight
On November 19, 2013, at 1810 mountain standard time, a Cessna T210M airplane, registration N6832B, impacted terrain near Cedaredge, Colorado. The pilot, the sole occupant, was fatally injured and the airplane was destroyed. The airplane was registered to and operated by Montana National Incorporated under 14 Code of Federal Regulations Part 91 as a personal flight. Night conditions existed at the time of the accident, and no flight plan was filed. The flight departed Zamperini Field Airport (TOA), Torrance, California at 1448 and was destined for Aspen-Pitkin County Airport (ASE), Aspen, Colorado.
According to voice recordings from the Federal Aviation Administration (FAA), the airplane was inbound to ASE at 13,500 feet mean sea level (MSL), with the pilot receiving visual flight rules (VFR) flight following from Denver Air Route Traffic Control Center (ARTCC). The pilot requested an instrument flight rules (IFR) clearance about 55 miles southwest of ASE. The controller issued an IFR clearance to ASE at 15,000 feet MSL and requested flight plan information.
While transmitting flight plan information, the controller observed the airplane make a significant left turn (about 180 degrees) away from the assigned clearance. When asked, the pilot stated that his autopilot had disconnected. The controller then issued a heading back towards ASE, which the pilot accepted. The airplane continued turning left and made a rapid descent. Radar and radio contact were subsequently lost.
Personnel Information
The pilot, age 57, held a private pilot certificate with airplane single-engine land and instrument ratings. On March 1, 2013, he was issued a Class 3 medical certificate requiring corrective lenses for near vision. At that examination, he reported 1,560 hours total flight experience, with 50 hours in the last six months. He reported 950 hours in the accident airplane make and model on his May 16, 2013 insurance policy renewal. Recent logbooks were not available.
He received his instrument rating on August 8, 2011. The recommending flight instructor described him as thoughtful, analytical, with strong flying skills. Training flights occurred in Southern California, typically in stratus clouds. About a month before the accident, the pilot flew instrument approaches into TOA with a friend as safety pilot.
Aircraft Information
The accident airplane, a 1978 Cessna T210M, was registered to Montana National Inc. It received a standard airworthiness certificate on August 14, 1978. It was equipped with a Continental TSIO-520R engine (serial 512927). The last annual inspection was May 15, 2013, at 3,549.5 hours total time.
The airplane had a Garmin GNS-430 GPS/navigation/communications transceiver and a Cessna 400B Nav-O-Matic autopilot. On January 18, 2008, a DAC International GDC 31 Roll Steering Converter was installed, interfacing with the autopilot. On January 24, 2012, an overhauled attitude indicator and horizontal situation indicator (HSI) were installed.
A dual pump vacuum system was installed. Both vacuum pumps were replaced on August 3, 2012. During the May 15, 2013 annual inspection, air and vacuum filters were replaced. No other maintenance entries for vacuum or avionics systems followed.
Meteorological Information
The weather observation station at Blake Field Airport (AJZ), Delta, Colorado, about 14 miles southwest of the accident site, reported at 1815: wind 120 degrees at 4 knots, visibility 10 miles, broken clouds at 5,000 feet AGL, overcast at 6,500 feet AGL, temperature 7°C, dew point -2°C, altimeter 29.95. AJZ elevation is 5,193 feet MSL. An AIRMET for moderate turbulence and icing was active in the accident area.
Regional NEXRAD radar for 1815 showed light reflectivity values of 2, consistent with snow showers, near the accident location.
Wreckage and Impact Information
The airplane impacted hilly, vegetated terrain and came to rest relatively upright, leaning left on a rock-covered hill. The cabin and instrument panel were consumed by post-impact fire.
Several components separated from the main wreckage. A 15-foot outboard section of the left wing was located about 1,450 feet away on a 311-degree heading. A 14-inch section of the left aileron outboard end, over four feet of the left flap outboard end, and fragments of the left horizontal stabilizer and elevator also separated.
The fractured left spar and upper wing skin were bent aft and upward, consistent with wing separation in a positive load. The left horizontal stabilizer leading edge exhibited impact damage consistent with being struck by the separated left wing. All separations appeared characteristic of overload.
Aileron flight control system examination revealed signatures consistent with aileron flutter. The left aileron/flap interconnect push-pull tube had torn through the spar web and impacted the left aileron stop bolt bracket, which was bent and separated. Left and right aileron stop bolt heads and bell crank stops exhibited hammered flat spots and metal smearing.
The attitude indicator gyro showed rotational scoring. Both vacuum pumps were disassembled; housings had impact damage, plastic drive couplings could not be rotated due to thermal damage, carbon vanes were intact, rotors fractured. Vacuum and avionics systems could not be tested due to fire damage.
The engine sustained thermal damage to the ignition harness and severe impact damage to cylinders 2, 4, and 6. Cylinders 1, 3, and 5 remained attached with thermal damage. Magnetos were thermally damaged and broken from mountings; spark could not be determined. Spark plugs exhibited normal color. Fuel pump and drive coupling intact. Fuel manifold attached, diaphragm thermally damaged. All fuel lines and injectors attached. Fuel screen clear.
Examination of airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
Additional Information
The unpressurized airplane had been level at 13,500 feet MSL for about 3 hours. Six oxygen cylinders were onboard; it could not be determined if the pilot was using them due to fire.
According to his wife, the pilot frequently flew with a pulse/blood oxygen sensor, monitoring blood oxygen percentage to fly extended periods at high altitude without supplemental oxygen. Throughout the flight, his communications to ATC and Flight Watch were coherent and rational.
Communications
The pilot received a preflight weather briefing from Prescott FSS at 1230. The briefer pointed out an AIRMET for moderate turbulence and icing valid from 8,000 feet MSL to FL200 within the last 120 miles of the planned route.
During the flight, the pilot obtained four weather updates via radio from Prescott Flight Watch at 1529, 1652, 1721, and 1802. Each update informed him of the icing AIRMET west of ASE. During the 1802 update, the pilot stated he had started to encounter snow from above, but it was clear to the ground.
After departure, he received VFR flight following from FAA ATC. At the time of the accident, he was in communication with Denver ARTCC. The following summary occurred:
- 1801: Pilot asked to go off frequency for Aspen weather.
- 1805: Reported back, given new Grand Junction altimeter.
- 1806: Requested IFR clearance to Aspen. After discussion, clearance issued.
- 1807: Controller asked to read IFR flight plan info; pilot complied.
- 1808: Controller asked if making a 360-degree turn; pilot said autopilot disconnected.
- 1809: Controller assigned heading for Red Table VOR.
- 1810: After noticing descent, controller asked to verify altitude; no response. Two more calls followed.
Medical and Pathological Information
An autopsy on November 20, 2013, by the Delta County Coroner determined the cause of death as blunt force injuries. FAA's Civil Aeromedical Institute performed toxicology tests; no tested drugs were detected.
Tests and Research
An NTSB radar performance study showed that from 1800:00 to 1806:35, the airplane flew straight and level at 13,400 feet MSL. Shortly after receiving IFR clearance to climb to 15,000 feet, the airplane reached a maximum altitude of 14,300 feet MSL during a climbing left turn, with airspeed decaying to about 95 knots. As the left turn continued, a rapid descent of over 20,000 feet per minute occurred, with maximum airspeed about 250 knots. The airplane completed a 360-degree left turn and impacted terrain about 20 seconds later.