ERA24FA176

The pilot departed on an instrument flight rules cross-country flight. About 15 minutes after departure, shortly after reaching a cruise altitude of 8,000 ft mean sea level (msl), the pilot reported to air traffic control that he was “picking up moisture in the clouds” and asked for a course deviation or a higher altitude. The controller approved course deviations and cleared the pilot to climb to 10,000 ft msl, which the pilot accepted. A performance study of the airplane’s ADS-B flight track data showed that the airplane’s airspeed decreased during the subsequent climb, and the airplane reached a maximum altitude about 8,500 ft msl and a minimum airspeed around 80 knots (kts) before it rapidly rolled left and lost altitude at a rate of about 1,300 ft per minute, consistent with an aerodynamic stall. The airplane briefly leveled off before entering a descending right turn, reaching a descent rate of 6,000 ft per minute. The descending turn continued until flight track data was lost at an altitude about 5,750 ft msl. At this time, the airplane’s calculated calibrated airspeed was about 210 kts; the airplane’s published never-exceed speed (Vne) was 197 kts indicated airspeed. A witness on the ground near the accident site observed the airplane “twirling” as it descended below the clouds and also observed debris falling from the sky. The wreckage was distributed over a distance of more than 10,000 ft, consistent with an in-flight breakup. Postaccident examination of the airplane and engine revealed no evidence of a mechanical failure that would have precluded normal operation. Control cable separations and airframe structural fractures all exhibited characteristics consistent with overload failure. The airplane was not equipped with anti- or de-icing equipment and was not certified for flight into known icing conditions. Review of weather information for the area indicated cloud bases around 4,500 to 5,000 ft with tops around 18,500 ft. The freezing level was around 5,500 ft, with supercooled large droplets (SLD) likely between 6,000 and 8,000 ft. The pilot filed his instrument flight plan for the accident flight with a flight planning application that generated a route briefing. The briefing contained weather information for the route of flight, including the forecast for moderate icing conditions; however, information regarding the potential SLD conditions would have been contained in supplemental icing information not provided in the standard briefing. Whether the pilot accessed supplemental icing information before the flight could not be determined. Flight track information indicated that the airplane likely entered instrument meteorological and icing conditions shortly after takeoff, and that the airframe and flight control surfaces began to accumulate ice rapidly, as the time between the pilot’s request for a higher altitude and the loss of flight track data was about 2 minutes. The airplane then likely encountered an aerodynamic stallwhile flying at an airspeed of 80 kts (15 kts faster than its maximum published stall speed). This was consistent with the effects of increased drag and stall speed due to ice accretion. It is likely that the pilot lost control of the airplane following the initial aerodynamic stall and was unable to recover. During the subsequent descending turn, the airplane exceeded its structural limitations, resulting in an in-flight breakup. The pilot held an instrument rating; however, review of available logbook information indicated limited recent instrument experience, with two instrument approaches and one holding procedure conducted during an instructional flight about 7 months before the accident. Whether the pilot’s loss of airplane control was the result of his inability to control the airplane due to ice accretion, a lack of proficiency in instrument flight, or a combination of those factors, could not be determined. Although the pilot’s awareness of the potential for SLD could not be determined, the route briefing generated at the time he filed the flight plan provided adequate information to alert him to the potential for icing conditions along his intended route of flight. Nevertheless, the pilot chose to depart and continue into an area with a known potential for icing conditions in the airplane that was not equipped to do so.

According to the airplane’s flight manual, the airplane was limited to Day/Night VFR and Day/Night IFR for “Non-Icing” operations only. This restriction was mandated by FAA Type Certificate Data Sheet Note 2 and required a placard noting the limitations that must be displayed in view of the pilot. The airplane’s published stall speed was 65 knots indicated airspeed (KIAS). The airplane’s published never-exceed speed (Vne) was 197 KIAS. On April 12, 2024, about 1633 eastern daylight time, a Piper PA-32R-301 airplane, N9236J, was destroyed when it was involved in an accident near Knoxville, Tennessee. The commercial pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to Federal Aviation Administration (FAA) air traffic control information, the pilot contacted clearance delivery at McGhee Tyson Airport (TYS), Knoxville, Tennessee, about 1611 and was cleared to Gerald R. Ford International Airport (GRR), Grand Rapids, Michigan, as filed. The pilot acknowledged the clearance and reported having the current weather information for TYS. At 1616, the local controller cleared the flight for takeoff from runway 23L and instructed the pilot to fly the runway heading. After departure, the pilot was instructed to turn right and proceed direct to GRR while climbing to 8,000 ft mean sea level (msl). About 1619, the pilot contacted departure control and continued the climb. A performance study of the airplane’s flight path based on ADS-B data showed that the airplane turned right onto a northerly heading around 1621 while climbing at airspeeds that were calculated to be between 85 and 105 kts. About 1628, the airplane leveled off around 8,000 ft msl. At 1631:27, the pilot contacted the controller and stated that he was “picking up a little moisture in the clouds” and requested deviations or a higher altitude. The controller approved lateral deviations and offered a climb to 10,000 ft msl, which the pilot accepted. The airplane resumed climbing about 1632, during which its airspeed rapidly decayed from about 120 kts to 80 kts. At 1632:33, the airplane reached a maximum altitude of 8,500 ft msl, which coincided with its lowest speed of 80 kts. The airplane then rolled left and turned more than 90° in 11 seconds while descending at a rate of 1,300 ft per minute. Between 1632:42 and 1632:47, the airplane leveled off about 8,200 ft msl. Shortly thereafter, airspeed began to increase and the airplane entered a right turn. About 1633:03, the airplane entered a rapid descent, reaching a rate of about 6,000 ft per minute. About 1633:15, the pilot transmitted “mayday, mayday, mayday.” The controller responded and observed the airplane in a spiraling descent. No further communications were received from the pilot. The last recorded ADS-B position at 1633:33 indicated that the airplane was descending through approximately 5,750 ft msl with a groundspeed about 223 kts and its calibrated airspeedwas about 210 kts. A witness reported hearing an airplane that sounded like it was “over-revving” and observed the airplane “twirling” as it descended below the clouds. The witness subsequently observed airplane debris falling from the sky before ground impact. An autopsy of the pilot’s remains was performed by the Knox County Regional Forensic Center as authorized by the Anderson County Medical Examiner. According to the autopsy report, the cause of death was blunt force injuries and the manner of death was accident. The FAA Forensic Sciences Laboratory performed toxicological testing of the pilots remains and detected ethanol at 0.02 g/dL in the pilot’s vitreous fluid and at 0.019 g/dL in the pilot’s urine. Ethanol was not detected in liver or brain tissue. Acetone was detected in urine, but not in vitreous fluid, liver tissue, or brain tissue. Ibuprofen was detected in liver tissue and urine. Ethanol is the intoxicating alcohol in beer, wine, and liquor, and, if consumed, can impair judgment, psychomotor performance, cognition, and vigilance. FAA regulation imposes strict limits on flying after consuming ethanol, including a prohibition on piloting a civil aircraft while having a blood ethanol level of 0.04 g/dL or greater. Alcohol consumption is not the only possible source of ethanol in postmortem specimens. Ethanol may sometimes be produced by microbes in a person’s body after death, potentially elevating ethanol levels in some postmortem specimens but not others. Postmortem ethanol production is made more likely by extensive trauma, which can spread microbes. Vitreous fluid and, to a lesser extent, urine, are generally better protected against the spread of microbes and therefore are generally less susceptible to postmortem ethanol production than are other specimen types. However, postmortem ethanol production can occur in vitreous and urine. Weather observations at TYS about the time of departure included wind from 280° at 13 kts, gusting to 24 kts, 10 statute miles visibility, light rain, scattered clouds at 5,000 ft above ground level (agl), a broken ceiling at 6,500 ft agl, and an overcast layer at 7,500 ft agl. ATIS information current at the time of departure included light rain and advisories for low-level wind shear. AIRMETs for icing, mountain obscuration, and moderate turbulence, as well as a convective SIGMET, were in effect for the region of the accident site at the time of the accident. Available meteorological data indicated cloud ceilings between 4,500 ft and 5,000 ft msl, with cloud tops around 18,500 ft msl. A high resolution rapid refresh model atmospheric sounding indicated a freezing level around 5,500 ft msl, with moderate clear, rime, and mixed icing indicated between 6,000 and 15,000 ft msl. The sounding also identified maximum vertical velocities exceeding 4,000 ft/min. Weather surveillance radar imagery indicated that the airplane entered an area of precipitation beginning around 1624 and continued into an areaof rain shower activity about 1627, as shown in the figure, below. Figure. Weather surveillance radar imagery for a scan initiated at 1627:33. The accident site is marked with a red circle and the location of the airplane at the time of the scan is shown in a black circle. The magenta line depicts the airplane's flight track. Icing probability and severity information, contained in the forecast icing product (FIP) and current icing product (CIP) imagery, indicated likely icing conditions between 1600 and 1700 in the area of the accident site, with greatest intensities between 7,000 ft and 8,000 ft msl. FIP/CIP imagery also indicated the likelihood of supercooled large droplet (SLD) icing conditions between 6,000 ft and 8,000 ft above the accident site. According to an air traffic control services review, no pilot reports of icing were received from other aircraft in the area during the hour preceding the accident. Precipitation in the form of light rain was present at the time of departure. Information provided by ForeFlight indicated that the pilot filed his instrument flight rules flight plan through the application and a briefing was generated. This briefing contained all standard weather information forecast before 1547, including AIRMETs and PIREPs. The briefing also contained a chart showing moderate icing conditions at 6,000 ft and above through the first half of the filed route, but did not contain the FIP/CIP products that indicated the potential for SLD icing. According to ForeFlight, the pilot did not access weather imagery from his account before the accident flight. According to FAA Advisory Circular 91-74B, “Pilot Guide: Flight in Icing Conditions,” supercooled large drops are water drops with a diameter greater than 0.05 millimeters that exist in a liquid form at air temperatures below 0°C. The AC stated that SLD can result in ice accretions that cause, “very rapid and dangerous stall speed and drag increases for some aircraft, and roll control anomalies for others.” Regarding preflight planning, the AC stated that pilots can reasonably expect inflight icing when flying in clouds with temperatures at or below 0°C (32°F), and that: It is critically important for pilots to obtain the freezing levels for the areas in which they will be flying to be able to make educated decisions on how to exit icing conditions if they are encountered. The pilot held a commercial pilot certificate with an instrument rating. A review of available logbook information indicated limited recent instrument flight experience, including 1.8 hours of dual instruction with two instrument approaches and one holding procedure recorded about seven months before the accident. The airplane impacted wooded terrain near a residential area. The fuselage was found nose-down, and both wings were separated from the fuselage. The debris field extended over a distance of several thousand feet. The left wing was located about 2,481 ft from the main wreckage, the rudderabout 4,707 ft, the horizontal stabilizer about 5,979 ft, and a portion of the right fuel tank about 10,260 ft from the fuselage. Examination of the flight control system revealed continuity from the cockpit to the control surfaces, except for separations consistent with overload, or with cuts made during recovery. Several control cable ends exhibited a “broomstraw” appearance consistent with tensile overload failure. The wing main spar fracture surfaces exhibited a dull, granular appearance. Portions of the wings were fragmented and distributed along the debris path. The engine was partially buried at the accident site. A post-recovery examination revealed mechanical continuity of the crankshaft and camshaft, and no evidence of preimpact anomalies or internal failure. Fuel was present in the fuel system components examined, and no contamination was observed. The three-bladed propeller remained attached to the engine. Two blades remained secured in the hub, and one blade was separated. The blades exhibited leading edge damage, chordwise scratching, and torsional twisting consistent with rotation under power at impact.