Synopsis
On February 2, 2017, about 1955 central standard time, a Mooney M20C, registration N9149V, struck a field in Ellendale, Minnesota, following pilot incapacitation during flight. The pilot sustained serious injuries, and the airplane was substantially damaged. The aircraft was operated under 14 CFR Part 91 as a business flight by the pilot-owner. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was active. The flight departed Duluth International Airport (DLH) at 1808, destined for Winona Municipal Airport (ONA).
Flight History
Earlier that day, the pilot flew from ONA to Thunder Bay, Ontario (CYQT). He reported using the cabin heater continuously due to cold weather. During the last 10–15 minutes of the 2-hour 30-minute flight, he developed a slight headache. After landing, the headache persisted, accompanied by a sensation he described as "butterflies" in his stomach, which he attributed to anxiety about customs procedures and a possible lack of caffeine or illness. The headache subsided after drinking coffee. He departed CYQT around 1600 for a 1-hour 20-minute flight to DLH, feeling headache-free, but the headache returned after landing.
At DLH, the pilot expedited ground time due to cold-start concerns. He started the engine and filed his flight plan while seated in the cockpit. He received an IFR clearance to fly as filed to ONA at 6,000 ft msl, with a planned climb to 9,000 ft msl after 10 minutes. While taxiing, he again experienced "butterflies," more intense than before. The symptoms subsided by the runway, but he became "hyper focused," performing the engine runup and takeoff checklist repeatedly. A tower controller asked if he was ready, which broke his fixation. ATC recordings show the engine was running for at least 12 minutes before takeoff.
Accident Sequence
The pilot recalled being cleared to a heading of 240° and setting the autopilot. During climb, he felt another wave of "butterflies," activated the autopilot, and then lost consciousness. The last communication was at 1812:18 when he attempted to contact departure control on the wrong frequency. Controllers at DLH and Minneapolis Center attempted to reach him, including via other aircraft. Radar showed the airplane tracking 190–200° at altitudes exceeding 12,000 ft msl. The final radar contact at 1952:47 showed the aircraft at 2,300 ft msl about 1 mile north-northeast of the accident site, 80 miles west of ONA.
The pilot remained unresponsive until after impact in a relatively level attitude. He awoke, confused, thinking he had fallen asleep briefly. He reached through a hole in the windscreen and realized he was no longer flying. He extricated himself and walked to a house about 500 ft away. A 911 call from the house was placed at 2107.
Postaccident Examination
Both fuel tanks were empty. The cabin heat control was fully on, and the cabin vent was off. The exhaust muffler exhibited several cracks, one with soot deposits on the fracture surfaces. The exhaust shroud and connecting scat tubing showed sooting. The pilot reported using the heater at maximum during all three flights and had no carbon monoxide (CO) detector aboard. Maintenance records indicated a new exhaust system installed in January 2007 at tachometer 2,343 hours, with the last annual inspection on February 2, 2016, at 2,998 hours. Accident tachometer time was 3,081 hours.
Medical Findings
Postaccident medical records reviewed by the NTSB Chief Medical Officer stated the pilot was treated for injuries and frostbite. Blood drawn at 0018 the following morning showed a CO level of 13.8%. The pilot was a nonsmoker. Given CO's half-life of 4–5 hours when breathing ambient air, the estimated CO level at the time of the accident was at least 28%, likely higher due to postaccident oxygen administration. CO is an odorless, tasteless, colorless, nonirritating gas that binds to hemoglobin, impairing oxygen transport.