NTSB CAROL · Event
Event WPR22FA023
Aircraft involved
Probable cause & findings
The pilot’s decision to fly the airplane into known icing conditions, which resulted in a loss of airplane control and collision with terrain.
Factual narrative
HISTORY OF FLIGHTOn 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 Title 14 Code of Federal Regulations Part 91 personal flight. The pilot had purchased the airplane just days before the flight and was flying it from the purchase location of 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 he received a ForeFlight weather briefing that identified moderate icing conditions along the planned route of travel. The relative humidity during the planned time along the route of flight was 98%. The weather briefing indicated that during the planned flight time, the base freezing level was 5,000 ft msl and the top freezing level was 22,000 ft msl. A review of air traffic control (ATC) communications and radar data revealed that the airplane departed AWO about 0842. The pilot initiated an eastbound turn, which was abnormal for departures from AWO airport, and the controller questioned the pilot about the abnormal turn and subsequently issued the pilot a heading to the south. The pilot advised ATC that the turn was not intentional and that the autopilot may have been the issue. The pilot corrected course; however, at 0900, the airplane made a hard right turn to the northwest in the opposite direction of the planned route of flight. The airplane’s altitude was about 14,000 ft msl when a handoff was made from the Seattle Terminal Radar Control Approach facility to the Seattle Air Route Traffic Control Center. The pilot established communication with the ARTCC controller and stated that he had an issue with the autopilot and that he was correcting to the southeast. The airplane’s altitude was about 14,000 ft msl when the pilot made a left turn to the southeast, and the controller acknowledged the heading correction and subsequently cleared the airplane to depart 14,000 ft msl and climb to 17,000 ft msl. The controller made the pilot aware of multiple pilot reports (PIREPs) for moderate rime icing conditions between 12,000 ft msl and 18,000 ft msl. The controller offered the pilot an altitude of 19,000 ft msl to get above the ice, and the pilot accepted. At 0903, the airplane’s altitude was 16,000 ft msl when the controller informed the pilot that he was about 20° left of course and to maintain his present heading. About 0904, after climbing to an altitude of 16,300 ft msl, the airplane began a rapid descent with a series of tight spiral turns. Communication between the controller and the pilot became broken and unreadable. The controller solicited an airplane in the area to attempt communication with the accident airplane on the emergency frequency 121.5 and to relay the controller’s instructions. After multiple attempts to communicate, the relaying airplane informed the controller that the pilot of the accident airplane reported that the airplane was out of control. The airplane descended through 5,400 ft msl when a simultaneous loss of radar contact and communication occurred shortly after 0910. The airplane was the subject of an alert notice and was located by search and rescue personnel in the Snoqualmie National Forest, Snoqualmie, Washington, about 1 mile southeast of Calligan Lake. PERSONNEL INFORMATIONAccording to a friend of the pilot, the pilot transitioned from the use of a paper logbook to ForeFlight’s pilot logbook. Foreflight indicated that the pilot had amassed 1,561.4 hours of flight experience. Following a 6-year hiatus from flying, the pilot resumed flying 5 months before the accident and had amassed 13.4 hours of flight experience in a Cessna 172. Further, the Foreflight track log identified six flights in the accident airplane that were not documented in the pilot’s logbook. The six flights were conducted over the 3 days before the accident and totaled 5.1 hours of flight time. The pilot’s logbook contained no record of a flight review or an instrument proficiency check since the pilot had resumed flying. AIRCRAFT INFORMATIONAccording 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 by the previous owner at the time of the sale and were not located during the investigation. The previous owner surmised that the logbooks were on board the airplane at the time of the accident. METEOROLOGICAL INFORMATIONA review of the meteorological conditions that existed surrounding the time of the accident revealed instrument meteorological conditions. AIRMET Z was active for light to moderate rime icing and the presence of clear ice conditions. PIREPs confirmed the icing conditions and low-level turbulence in the vicinity of the accident site. The northwest section of the Surface Analysis Chart at 0800 depicted a low-pressure system over the Washington Pacific coastline associated with a frontal wave, with a warm front extending southeastward over Washington and in the immediate vicinity of the accident site. A secondary trough of low pressure extended southeastward from the front across Washington, northeast Oregon, and into western Idaho. A high-pressure system was located over central Idaho. The station models in the vicinity of the accident site depicted light winds, obscured skies in rain and fog, with temperatures ranging from 50°F in the Seattle area to near 37° F immediately southeast of the accident site at Ellensburg, Washington. Temperature-dew point spreads were less than 2° F over the area with light rain and fog. To determine the conditions over the accident site, a high-resolution rapid refresh (HRRR) numerical model was obtained from the National Oceanic and Atmospheric Administration Air Research Laboratory archive for the nearest grid point to the accident site about the time of the accident. The HRRR sounding depicted an accident site elevation near 3,681 ft, with cloud tops estimated at 20,000 ft msl. The freezing level was identified at 6,000 ft msl and indicated a high potential for light-to-moderate clear icing and rime ice from the freezing level through 20,000 ft msl. AIRPORT INFORMATIONAccording 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 by the previous owner at the time of the sale and were not located during the investigation. The previous owner surmised that the logbooks were on board the airplane at the time of the accident. WRECKAGE AND IMPACT INFORMATIONThe airplane wreckage was located in densely wooded, mountainous terrain and distributed within a 21 ft by 15 ft area. Damage to the outboard left and right wings was consistent with the airplane initially impacting two trees about 20 ft above the base of the trees. The northwestern border of the wreckage consisted of the engine and propeller sections, which sustained thermal damage. The Nos. 1 and 2 cylinders were liberated from engine block, and the three propeller blades were liberated from the propeller hub. The cabin and fuselage were consumed by the post-impact fire. The airplane’s tail section including the rudder and elevators, formed the southwestern border of the wreckage. An examination of the engine and airframe revealed no anomalies or mechanical malfunctions that would have precluded normal operations. The airplane’s anti-ice and de-ice systems had sustained significant thermal damage. The TKS ice protection panels affixed to the leading edges of the vertical and horizontal stabilizers were present and had sustained thermal damage. The windshield spray-bar that provided de-ice protection and the propeller slinger ring that also provided de-ice protection were not visibly identifiable. The propeller blades were equipped with de-icing boots and had sustained thermal damage. The supplement to the pilot’s operating handbook and the airplane flight manual contained a warning that stated, “INTENTIONAL FLIGHT INTO KNOWN ICING IS PROHIBITED.” After a 6-year hiatus from flying, the pilot had just purchased the airplane. The morning of the accident flight, he filed an instrument flight rules (IFR) flight plan and received a weather briefing that identified icing conditions along the planned flight route. The pilot departed the airport about 0842 and planned to climb to an altitude of 17,000 ft mean sea level (msl). About 0901, the controller cleared the pilot to depart 14,000 ft msl and climb to 17,000 ft msl. Subsequently, the controller informed the pilot of multiple PIREPs for icing conditions from 12,000 ft msl to 18,000 ft msl and offered the pilot an altitude of 19,000 ft msl to get above the icing, which the pilot accepted. About 0904, after climbing to an altitude of 16,300 ft msl, the airplane began a rapid descent with a series of tight spiral turns. Communication between the controller and the pilot became broken and unreadable. An airplane operating in the area relayed to the controller that the pilot reported being out of control. Shortly after 0910 radar contact was lost, and the airplane impacted terrain. It is likely that the accident airplane encountered structural icing and that the erratic turns coupled with a rapid descent rate were indicative of the pilot’s loss of airplane control, which resulted in a collision with terrain. Postaccident examination of the engine and airframe revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The supplement to the pilot’s operating handbook and the airplane flight manual contained a warning that stated, “INTENTIONAL FLIGHT INTO KNOWN ICING IS PROHIBITED.” The pilot’s logbook contained no record of a recent instrument proficiency check. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).
- — Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Pilot
- — Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-Conducive to structural icing-Effect on equipment
- — Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-Conducive to structural icing-Effect on operation
- — Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot
Verbatim from NTSB's published report. Source file
NTSB_2021_WPR22FA023.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (icing, turbulence, autopilot). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
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- NASA NTRS 2026 · Contractor Report (CR)
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- Embry-Riddle Scholarly Commons 2025 · Journal article (JAAER)
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- Embry-Riddle Scholarly Commons 2025 · Journal article (JAAER)
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