On April 10, 2013, about 0926 Pacific daylight time, a Cirrus Design Corporation SR22, N205KT, was substantially damaged when it impacted terrain in autopilot-controlled descent after the pilot became incapacitated during cruise flight near Silver Peak, Nevada. The private pilot, the sole occupant on board, was seriously injured. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal cross-country flight, which had originated from the Henderson Executive Airport in Las Vegas, Nevada, about 0752. A flight plan had not been filed. Witnesses reported to local authorities that an airplane had crashed in the desert near the Heart of Nature alum mine in Esmeralda County, Nevada. Local law enforcement personnel responded to the accident site and found the airplane relatively intact with the wings, empennage, and engine still attached to the fuselage and the injured pilot seated in the left front seat. The officer asked the pilot what happened, and the pilot was unable to respond coherently and mumbled what sounded like "I fell asleep" or "I just wanted to sleep." The day after the accident two Federal Aviation Administration (FAA) inspectors visited the pilot in the hospital. The FAA inspectors asked the pilot to explain what happened during the accident, and the pilot responded by stating that he made an attempt to take his own life. The pilot said that after takeoff, he flew south, climbed to 16,500 feet msl, and entered a waypoint into the GPS that was about 500 miles away. He explained that he planned the flight to avoid populated areas. He said that he switched the fuel selector to a tank that contained 20 gallons of fuel, and he estimated that the airplane would run out of fuel in slightly more than an hour. The pilot stated that he then took 40 1-milligram sleeping pills. He further stated that his next memory was waking up in the hospital. When the airplane was recovered by salvage personnel, FAA inspectors examined the airplane and reported that the nose landing gear was bent aft, and both main landing gears were bent upward and outboard. The forward lower part of the fuselage was crushed and deformed upward and aft. Several attempts were made to interview the pilot over a 6-month period, and to obtain a completed National Transportation Safety Board Form 6120.1 Pilot/Operator Aircraft Accident/Incident Report from the pilot. The pilot declined to be interviewed, citing legal issues, and a completed Form 6120.1 was not received. According to data retrieved from non-volatile memory in the airplane's Avidyne primary flight display and multi-function display, the airplane flew south for about 22 nautical miles and then turned to a northwesterly heading of about 330 degrees. It climbed to an altitude of about 16,500 feet msl and maintained that altitude for approximately 1 hour 8 minutes. About 0917, when the fuel in the selected wing tank was exhausted, the engine lost power. The envelope protection feature of the airplane's Avidyne DFC90 autopilot placed the airplane into a controlled descent, which was maintained to ground impact. The recorded data showed that the airplane descended at an indicated airspeed that varied from 84 to 103 knots and a descent rate that varied from 1,100 to 1,500 feet per minute. The last data point recorded before ground impact showed that the airplane's indicated airspeed was 84 knots and its descent rate was about 1,500 feet per minute. According to Avidyne, the DFC90 autopilot's envelope protection feature operates whenever the autopilot is active. Envelope protection continuously computes the reserve lift available before stall may be expected, in all flight conditions. If a predetermined reserve lift threshold is violated, the autopilot will reduce the bank angle and/or lower the nose to reestablish operation within limits. The commanded autopilot mode is not cancelled. For example, if the autopilot is in navigation-coupled, altitude-hold mode, the autopilot will continue to follow the flight plan and will make its best attempt at maintaining altitude consistent with maintaining an acceptable stall margin. With wings level and a complete loss of engine power, the reserve lift threshold is maintained at approximately 1.1 times the stall speed; the airplane will descend as necessary to maintain that reserve.