N6609P

HISTORY OF FLIGHTOn May 18, 2016, about 0901 mountain daylight time, a Cessna P210N, N6609P, sustained substantial damage when it impacted a field in a flat spin about 4 miles northeast of Sheridan Lake, Colorado. The pilot sustained fatal injuries. The airplane was registered to and operated by Stubblefield Construction Company under the provisions of the 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed for the flight, which departed at 0645 from Rock Springs-Sweetwater County Airport (RKS), Rock Springs, Wyoming, en route to Wiley Post Airport (PWA), Oklahoma City, Oklahoma.

Earlier that morning, about 0222, the pilot departed Nampa Municipal Airport, Nampa, Idaho, and flew to RKS, where he landed the airplane about 0442. A witness at RKS reported that the pilot had the airplane topped off with 68 gallons of fuel. He reported that the pilot slept in the pilot's lounge for about 1 hour before departing toward PWA.

After departing RKS, radar data from the Federal Aviation Administration (FAA) indicated that the airplane was flying on a southeast heading at 17,300 ft pressure altitude. About 0800, the pilot established visual flight rules flight following with the Denver, Colorado, Air Route Traffic Control Center, which provided the pilot with the current altimeter setting.

A transcript of the communications between the accident airplane and an air traffic controller indicated that, at 0842:36, the pilot transmitted, "(unintelligible) I'm going down and I'm going down hard."

It became apparent to the controller that the pilot was experiencing some type of distress. The controller attempted to communicate with the pilot, concerned that he was possibly experiencing hypoxia, carbon monoxide exposure, or another medical condition that was affecting his speech and ability to control the airplane. Throughout the remainder of the flight, the controller provided numerous altimeter setting updates in a continued effort to communicate with the pilot; however, the pilot did not acknowledge or reply to numerous controller requests. The controller made numerous recommendations to the pilot to descend to a lower altitude.

At 0846:23, the controller transmitted, "November six six zero nine papa suggest you descend to lower altitude at or below one two thousand uhh sounds like you might have an hypoxic situation."

The recorded radar data indicated that the airplane had maintained a straight-and-level flight track to the southeast at 17,300 ft pressure altitude until 0847. Then, the airplane entered a series of turns, climbs, and descents that ultimately put the airplane on a northerly course.

At 0853:16, the pilot transmitted, "I can show you what a p two ten can do." The radar data indicated that the airplane's altitude was about 11,700 ft pressure altitude at the time of the transmission.

At 0854:05, the pilot transmitted, "(unintelligible) guys want me to do Muller?" The radar data indicated that the airplane's altitude was about 12,275 ft pressure altitude at the time of the transmission.

At 0855:24, the pilot transmitted, "I can show you things this airplane can do." The radar data indicated that the airplane's altitude was about 10,600 ft pressure altitude at the time of the transmission.

At 0858:01, the pilot transmitted, "Let me show you what a (unintelligible) two ten can do." The radar data indicated that the airplane's altitude was about 10,950 ft pressure altitude at the time of the transmission.

At 0858:28, the controller transmitted, "November six six zero nine papa it's possible you're uhh uhh hypoxic and umm and carbon monoxide poisoning is going on if you could just open up that window maybe get some fresh air in that airplane November zero nine pop."

At 0900:30, the pilot's last radio transmission stated, "You got it watch the center watch it go." The last recorded radar return at 0900:32 indicated that the airplane's pressure altitude was about 9,200 ft. Subsequent attempts to contact the pilot were unsuccessful.

Fig. 1 View of the airplane at the accident sitePERSONNEL INFORMATION

The 64-year-old pilot held a private pilot certificate with airplane single-engine land and instrument ratings. He held a third-class medical certificate issued on November 11, 2015, with a limitation for corrective lenses. During his medical examination in November 2015, the pilot reported that his total flight time was 4,250 hours. The pilot's logbook was not recovered during the investigation.

FAA airman records indicated that the pilot was involved in a landing incident in Boise, Idaho, on May 28, 2000. The pilot was found to be operating the airplane under the influence of alcohol with a blood alcohol concentration (BAC) of 0.26 percent, which was above the BAC legal limit of 0.04 percent for operating aircraft. The pilot surrendered his pilot and medical certificates after the incident. He reapplied for a medical certificate on July 5, 2005, and was granted an eligibility letter on August 10, 2005.

AIRCRAFT INFORMATION

The airplane was a pressurized, single-engine Cessna P210N that was manufactured in 1979. The airplane was configured to seat 4 individuals and had a maximum takeoff weight of 4,000 lbs. The airplane was equipped with a 310-horsepower Continental TSIO-520-P engine and a 3-blade McCauley propeller. No acrobatic maneuvers, including spins, were approved. The last annual maintenance inspection was conducted on June 1, 2015. The total airframe time at the time of the inspection was 3,329 hours, and the total engine time was 1,035 hours. According to available documentation, the airplane was flown about 28 hours since the last annual inspection.

METEOROLOGICAL INFORMATION

At 0853, the surface weather observation at Lamar, Colorado, located about 30 nautical miles southwest of the accident site, included wind from 160° at 9 knots, variable between 140° and 200°, surface visibility 10 miles, clouds broken 6,500 ft above ground level, temperature 13°C, dew point 6°C, and an altimeter setting of 30.25 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted an open, harvested agricultural field in a wings-level, flat pitch attitude. The left wing was canted aft and the right wing was canted forward, consistent with the airplane being in a left spin at impact. The tail was bent slightly to the left of the fuselage and the engine was displaced slightly to the right. The fuselage was leaning slightly to the left. The landing gear was found in the retracted position.

The left wing remained attached to the fuselage. It was bent downward at the root and bent upward at the flap/aileron junction where the wing was resting on the ground. There was no leading edge compression damage observed to the left wing. The left flap was in the retracted position. The left main fuel tank was ruptured. There was no fuel in the left wing auxiliary fuel tank.

The right wing remained attached to the fuselage. It was bent downward at the root and bent upward in the middle of the right aileron where the wing was resting on the ground. No leading edge compression damage was observed to the right wing. The right flap was hanging down approximately 10°. Examination of the flap cables indicated the right flap cable was separated near the right wing root. The bottom side of the right wing had oil spray from the wing root extending toward the outboard end of the right flap. The right main fuel tank contained an undetermined amount of fuel. There was no fuel in the right wing auxiliary fuel tank.

The tail was fractured almost completely around its circumference at the dorsal. The rudder and elevators remained attached to the empennage. The rudder balance weight was separated from the top of the rudder and was found on the ground directly below the rudder.

The fuel selector handle was found positioned to the right tank, and the fuel selector valve was found in an intermediate position between RIGHT and OFF. The main fuel gauges indicated that the right tank was greater than 1/2 full and the left tank was full. The fuel strainer assembly was removed and contained about 4 ounces of fuel consistent with 100LL fuel; a sample tested negative for water contamination. The fuel strainer screen was installed properly with a cork gasket.

The airplane's pressurization system controls were on and the cabin pressure was set to 5,000 ft. The pressurization outflow and safety valve were examined. The outflow valve diaphragm was pliable and moved freely. The outflow valve was removed, and the diaphragm was compressed by hand. The pneumatic pressure port was covered to restrict airflow and the diaphragm did not move, which indicated normal operation. The safety valve was also removed for examination. The electric solenoid on the safety valve was found separated from the valve housing by impact damage. A fragment of the safety valve remained connected to the solenoid threads. The safety valve diaphragm was compressed, and a tear was observed where the solenoid had been installed. The "Overhead Vent Fan" switch was found in the LOW position.

The airplane was equipped with an aftermarket supplemental type certificate inflatable door seal. The cabin "Door Seal Activate" switch was observed to be in the OFF position.

Flight control cable continuity was confirmed from the flight controls to their respective attachment points of the elevator, rudder and ailerons. The flap actuator was found in the 0° position; however, the flap handle and flap indicator were in the 10° position. The elevator trim actuator was found in about a 5° tab up position.

The engine remained partially attached to the airframe by cables and lines; all four engine mount legs were broken. The exhaust and induction systems exhibited impact damage, and the oil sump was crushed upward into the crankcase. The throttle, mixtu...