WPR23FA141

The pilot’s continued visual flight into instrument meteorological conditions, resulting in airframe ice accretion and a subsequent loss of airplane control.

During a VFR flight, the non-instrument-rated pilot contacted air traffic control and requested flight following. The controller issued a discrete transponder code, and no additional communications were observed, and no services were provided. A review of Automatic Dependent Surveillance-Broadcast (ADS-B) data indicated that while en route, the airplane climbed to an altitude of 14,100 ft msl. The airplane then descended and maintained 13,900 ft msl for the next 6 minutes before making a sharp left turn from the north to west. ADS-B data indicated that after the left turn the remaining flight time was about 44 seconds. Witnesses on the ground near the accident site reported hearing the airplane operating in the area and looked up in the direction of the sound. However, they could not see the airplane or the 4,500 ft peak of a nearby mountain, as they were obscured by clouds. Another witness observed the airplane descending rapidly through the clouds in a nose-down attitude, followed by impact in mountainous terrain. Another witness reported that nearly 6 minutes after the initial impact, an empty parachute could be seen descending through the clouds. The accident site was in a location with clouds and areas of precipitation. Based on the meteorological information, clouds were likely present from 4,000 ft msl through 14,000 ft msl. Based on the accident airplane’s altitude of 13,900 ft msl, it likely stayed at or above the cloud tops and out of instrument meteorological conditions (IMC) until 0945, when it likely entered an area of cloud cover that contained conditions conducive to producing between a trace and moderate airframe icing. Icing can often be concentrated near the tops of the clouds. The pilot generated and received a commercial weather briefing before takeoff. The weather forecast at that time called for instrument flight rules (IFR) conditions, mountain obscuration, and moderate icing to 14,000 ft msl. Additionally, the graphical forecast for aviation indicated a broken to overcast cloud cover, with cloud bases at 7,000 to 9,000 ft msl expected for the accident site location and cloud tops forecast at 17,000 to 18,000 ft. Based on meteorological data, the accident airplane was likely in IMC and operating in conditions characterized by trace to moderate icing. According to the manufacturer’s pilot operating handbook (POH), flight into known icing conditions is prohibited. Additionally, the POH indicated that the airplane’s velocity never exceed airspeed (VNE) was 201 KIAS, and the maximum demonstrated parachute deployment speed (VPD) was 133 KIAS. According to ADS-B data, when the airplane’s groundspeed was 205 kts, the calculated true airspeed was 235 kts and the calibrated airspeed (CAS) was 200 kts, which exceeded the manufacturer’s VPD. Exceeding the manufacturer’s VPD likely resulted in the structural overload of the three-point harness straps that connected the airplane fuselage structure to the parachute canopy.

The accident pilot generated and received a weather briefing from ForeFlight at 0800 PDT that contained Graphical Airman Meteorological Forecast (G-AIRMET) Zulu and icing information, with a cross-section graphic and ground forecast for aircraft that indicated cloud coverage information. The weather forecast information applicable for the accident time indicated that both text Airman Meteorological Information (AIRMET) and G-AIRMETs Sierra and Zulu warned for IFR conditions, mountain obscuration, and moderate icing to 14,000 ft msl. In addition, the Graphical Forecast for Aviation indicated a broken to overcast cloud cover, with cloud bases between 7,000 and 9,000 ft msl expected for the accident site location and cloud tops forecast between 17,000 and 18,000 ft. The Winds and Temperature Aloft forecast valid for the area near the accident site indicated that at 12,000 ft msl the wind was out of 260°, the wind velocity was 31 kts and the outside air temperature was -19° C. The wind at 18,000 ft msl was out 260°, the wind velocity was 59 kts and the outside air temperature was -29° C. The accident site was in a location ahead of a mid-level trough, with the wind flow from the west and perpendicular to the mountain chain. Analysis of the meteorological aerodrome forecasts, weather radar, satellite imagery, and high-resolution rapid return refresh sounding by an NTSB meteorologist indicated that clouds were likely from 4,000 ft msl through 14,000 ft msl. The Forecast Icing Product and Current Icing Product imagery noted the icing category between a trace and moderate airframe icing. Icing can often be concentrated near the tops of the clouds. According to the manufacturer’s POH, flight into known icing conditions is prohibited. The pilot held a private pilot certificate, with an airplane single engine land rating that was issued without limitations November 12, 2022. The pilot’s logbook that contained flight training hours of experience and endorsements was not recovered during this investigation. The pilot reported zero total hours of civil flight experience at his medical examination dated August 31, 2022. As of January 11, 2023, the pilot maintained a ForeFlight pilot logbook; those records indicated that the pilot had accumulated 25.8 hours of flight experience in the accident airplane. No additional flight experience, endorsements, or limitations were recorded in the Foreflight data. The airplane’s maintenance logs were in the airplane at the time of impact. The propeller and engine logbooks were not recovered. The airframe logbook was recovered from the wreckage and showed that the last annual inspection occurred November 29, 2022. During that inspection, an entry likely referring to the Cirrus Aircraft Parachute System indicated, “secured CAPS ignition wiring rubbing on elevator cables.” Additionally, the inspection entry stated, “complied with Independent Component Analysis for precise O2 system.” At the time of the inspection, the airframe had accumulated 925.8 hours of operation. An annual inspection logbook entry dated May 19, 2022, indicated that the pitot and TKS routing inspection was completed, and a subsequent entry indicated that the TKS filter was replaced. Additionally, the logbook entry indicated that the airframe, engine, and propeller had amassed 810.7 hours of operation since new. According to the Oregon State Police Medical Examiner Division, due the condition of the pilot’s remains, no autopsy was performed. The Baker County Medical Examiner Report documented the pilot’s cause of death as blunt force trauma and manner of death was accident. The airplane impacted the ground in mountainous terrain at an elevation about 2,436 ft. The airplane impacted the west side of a mountainous ridgeline with a 33° slope. The airplane was highly fragmented. The wreckage sustained thermal damage that emanated from the impact crater. The main wreckage site was roughly 328 ft in diameter and the radius was marked by the impact crater, and spanned about 164 ft. The airplane fragmentation was consistent with a high-velocity impact. The impact crater spanned about 30 ft from east to west and about 22 ft from north to south, with crater depth being about 4 ft. All control surfaces were recovered. The top half of the vertical stabilizer and rudder were located about 1 mile north of the main wreckage. The upper 1/3 section of the vertical stabilizer and the complete rudder separated from the aft empennage. The vertical stabilizer leading edge through the trailing edge signatures were consistent with an object completely severing the upper 1/3rd section from the lower 2/3rd section. A corresponding signature was observed on the rudder, which presented a chordwise concave impression from the leading edge to just beyond the mid-chord point. The rudder remained in one piece with the upper and lower sections attached at the trailing edge, and witness marks inside of the impacted convex structure revealed about a 3/4-inch circular impression. There were no downed powerline wires in the area, and there weren’t any sections of the airframe suspended from the powerline wires. The CAPS parachute separated from the airframe, landed in the Snake River and after multiple attempts, was not recovered. The airplane was equipped with TKS, which provides anti-ice capability to the leading edges of the horizontal stabilizer, both wings, and the propeller blade faces via the slinger ring. The recoverable data module was found in the wreckage, but sustained impact damage that inhibited data recovery. The manufacturer’s POH indicated that the airplane’s VNE was 201 KIAS, and the VPD was 133 KIAS. On April 2, 2023, at 0950 Pacific daylight time (PDT), a Cirrus Design Corporation SR22, N424SW, was destroyed when it was involved in an accident near Oxbow, Oregon. The pilot and passenger sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The accident airplane departed Caldwell Executive Airport (EUL), Caldwell, Idaho, about 0930 under visual flight rules, with the intended destination of Lewiston Nez/Perce County Airport (LWS), Lewiston, Idaho. About 0934, while heading north at an altitude of 11,400 ft msl, the pilot contacted Big Sky Approach Control and requested flight following. The controller issued a discrete transponder code but did not provide the pilot with an altimeter setting and did not radar identify N424SW. No further communication occurred between the pilot and the controller. After contacting the Big Sky Approach Control, ADS-B data indicated that the airplane gradually climbed from 11,400 ft msl on a northerly heading to 14,100 ft msl. Shortly thereafter, the airplane descended and maintained 13,900 ft msl for about 6 minutes, then suddenly entered a sharp left turn to the southwest and increased groundspeed to 205 kts about 9:49:38. According to ADS-B data, after the sharp left turn, the airplane’s slowest groundspeed was 133 kts, and the maximum was 205 kts. Additionally, ADS-B data identified the airplane’s groundspeed was 205 kts, when the airplane’s heading was 246° magnetic and the airplane’s altitude was 12,300 ft msl. Witnesses on the ground near the accident site reported hearing the airplane flying and looked up in the direction of the sound. However, they could not see the airplane or the 4,500 ft peak of a nearby mountain, as they were obscured by clouds. Another witness observed the accident airplane descending through the clouds rapidly in a nose-down attitude, followed by impact in mountainous terrain. A post-impact fire ensued that was extinguished by area precipitation. Another witness reported that nearly 6 minutes after the initial impact, an empty parachute could be seen descending through the clouds. An Aerosance recoverable data module (RDM), a crash-hardened flight recording device, was installed in the tail