History of Flight
On October 28, 2021, about 0911 Pacific daylight time, a Mooney M20M, N40KA, was substantially damaged when it was involved in an accident near Snoqualmie, Washington. The private pilot sustained fatal injuries. The airplane was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
The pilot had purchased the airplane just days before the flight and was flying it from Arlington Municipal Airport (AWO), Arlington, Washington, to Magic Valley Regional Airport (TWC), Twin Falls, Idaho. The morning of the flight, the pilot filed an IFR flight plan from AWO to TWC and received a ForeFlight weather briefing that identified moderate icing conditions along the planned route. Relative humidity was 98% during the planned time. The briefing indicated the base freezing level was 5,000 ft mean sea level (msl) and the top freezing level was 22,000 ft msl.
Air traffic control (ATC) communications and radar data showed the airplane departed AWO about 0842. The pilot initiated an eastbound turn, abnormal for departures from AWO, and the controller questioned the pilot, who stated the turn was not intentional and that the autopilot may have been the issue. The pilot corrected course, but at 0900, the airplane made a hard right turn to the northwest, opposite direction. Altitude was about 14,000 ft msl when a handoff occurred from Seattle Terminal Radar Control Approach to Seattle Air Route Traffic Control Center (ARTCC).
The pilot told ARTCC he had an issue with the autopilot and was correcting to the southeast. At about 14,000 ft msl, the pilot made a left turn southeast, and the controller cleared him to climb to 17,000 ft msl. The controller advised the pilot of multiple pilot reports (PIREPs) for moderate rime icing between 12,000 and 18,000 ft msl and offered 19,000 ft msl to get above the ice, which the pilot accepted. At 0903, at 16,000 ft msl, the controller noted the pilot was 20° left of course and instructed him to maintain heading. About 0904, after climbing to 16,300 ft msl, the airplane began a rapid descent with a series of tight spiral turns. Communication became broken and unreadable.
The controller solicited a nearby airplane to relay instructions on emergency frequency 121.5. After multiple attempts, the relaying airplane reported that the accident pilot said the airplane was out of control. The airplane descended through 5,400 ft msl when radar contact and communication were lost shortly after 0910. Search and rescue located the wreckage in Snoqualmie National Forest, about 1 mile southeast of Calligan Lake.
Personnel Information
According to a friend, the pilot transitioned to ForeFlight’s pilot logbook. ForeFlight indicated the pilot had 1,561.4 hours of flight experience. After a 6-year hiatus, the pilot resumed flying 5 months before the accident and logged 13.4 hours in a Cessna 172. ForeFlight track logs identified six flights in the accident airplane over the 3 days before the accident totaling 5.1 hours, which were not documented in the pilot’s logbook. The logbook contained no record of a flight review or instrument proficiency check since resuming flying.
Aircraft Information
According to the previous owner, the airplane underwent an annual inspection on September 22, 2021. The airframe, engine, and propeller logbooks were provided to the pilot at sale but were not located during the investigation. The previous owner believed the logbooks were on board at the time of the accident.
Meteorological Information
A review of meteorological conditions showed instrument meteorological conditions (IMC) at the time. AIRMET Z was active for light to moderate rime icing and clear ice conditions. PIREPs confirmed icing and low-level turbulence near the accident site. The Surface Analysis Chart at 0800 depicted a low-pressure system over the Washington coastline associated with a frontal wave, with a warm front extending southeastward over Washington. A secondary trough extended southeastward across Washington, northeast Oregon, and into western Idaho. Station models showed light winds, obscured skies in rain and fog, temperatures ranging from 50°F in Seattle to 37°F southeast of the accident site, and temperature-dew point spreads less than 2°F with light rain and fog.
A high-resolution rapid refresh (HRRR) model for the nearest grid point indicated the accident site elevation near 3,681 ft, cloud tops estimated at 20,000 ft msl, freezing level at 6,000 ft msl, and a high potential for light-to-moderate clear and rime icing from the freezing level through 20,000 ft msl.
Wreckage and Impact Information
The wreckage was located in densely wooded, mountainous terrain within a 21 ft by 15 ft area. Damage to the outboard left and right wings was consistent with initial impact into two trees about 20 ft above ground. The engine and propeller sections formed the northwestern border and sustained thermal damage. Cylinders No. 1 and 2 were liberated from the engine block, and all three propeller blades were liberated from the hub. The cabin and fuselage were consumed by post-impact fire. The tail section, including rudder and elevators, formed the southwestern border.
Examination of the engine and airframe revealed no anomalies or mechanical malfunctions that would have precluded normal operations. The anti-ice and de-ice systems had sustained significant thermal damage. The TKS ice protection panels on the leading edges of the vertical and horizontal stabilizers were present but thermally damaged. The windshield spray-bar and propeller slinger ring were not visibly identifiable. The propeller blades were equipped with de-icing boots, which had thermal damage. The supplement to the pilot’s operating handbook contained a warning: “INTENTIONAL FLIGHT INTO KNOWN ICING IS PROHIBITED.”