NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The instrument-rated private pilot departed in the airplane on a cross-country flight under daytime instrument meteorological conditions (IMC). Throughout the first portion of the flight, the pilot was in contact with air traffic control (ATC) controllers. As the flight neared its destination, the pilot was instructed to turn the airplane to a heading of 030° and maintain an altitude of 4,000 ft mean sea level (msl). The pilot complied with the instructions and was told to change frequencies to another ATC sector. The new controller provided the pilot with an altimeter setting and approach information, which the pilot acknowledged receiving. A short time later, the controller issued the pilot directions to turn left to a heading of 290° and descend to 3,000 ft msl for a radar vector to the final approach course. Despite 10 attempts by the controller to reach the pilot, no response was received. About 3 minutes after the controller issued the initial heading and altitude change, the pilot transmitted that he was still on the 030° heading. The controller immediately responded to the pilot and provided him instructions to turn left and climb to 6,000 ft msl. The pilot did not respond, and the airplane continued on the 030° heading toward mountainous terrain with elevations above the airplane's 4,000-ft altitude. The controller made 17 additional attempts to communicate with the pilot over a period of about 5 minutes. There was no response before radar contact with the airplane was lost. The airplane impacted mountainous terrain near the last recorded radar target at an elevation of about 4,000 ft.
Weather data indicated that the flight would likely have been in IMC between 2,800 and 5,000 ft msl; therefore, the terrain would not have been visible to the pilot. However, avionics equipment installed in the airplane could have displayed a moving map showing the airplane's current position in relation to airports, and navigational aids.
The wreckage was severely fragmented and mostly consumed by a postimpact fire. The damage to the airplane was consistent with controlled flight into terrain. Although no evidence of preimpact mechanical malfunctions was found, the severity of the damage to the airplane precluded testing of the airplane's avionics equipment. It could not be determined why the pilot was unable to communicate with ATC or why he failed to maintain situational awareness and clearance from rising mountainous terrain.
The pilot's autopsy results revealed severe coronary artery disease, which placed the pilot at significantly increased risk of acute impairment or incapacitation by a cardiac event such as ischemia, a heart attack, or an arrhythmia, which could include symptoms ranging from chest pain, shortness of breath, or palpitations all the way to loss of consciousness. However, during the pilot's last transmission, he did not mention any such symptoms, and he did not seem to be in distress. Therefore, it is unlikely that an acute cardiac event caused or contributed to this accident. Toxicology testing identified the pilot's use of a potentially impairing drug, hydrocodone. However, there was no blood available for testing, and there is no method for calculating blood levels from liver or urine results. While the impairing effects of hydrocodone and its metabolite dihydrocodeine could have decreased the pilot's attentiveness or increased his susceptibility to a distraction, whether this occurred could not be determined.