WPR23FA080

The pilot’s failure to deice the airplane before takeoff in weather conditions conducive to ice accumulation, which resulted in an ice-contaminated wing and subsequent stall during takeoff.

The airplane was removed from a heated hangar and refueled, at which time water droplets were visible on both wings. The airplane remained outside for about 40 minutes, with no deice or anti-ice treatment, until takeoff was initiated. Multiple witnesses near the accident site reported observing the airplane take off and enter a nose-high attitude, after which it immediately rolled left and impacted the terrain. Wreckage and impact signatures at the accident site were consistent with the left wing impacting the runway surface before the nose of the airplane impacted terrain just to the left of the runway. Witnesses characterized the precipitation at the time of the accident as snow and misty rain, varying in intensity between light and medium. The airplane was equipped with a Wing and Horizontal Stabilizer Anti-Icing System to prevent and remove any ice formation on the leading edges of the wing and the horizontal stabilizer; the system is activated by a “Wing Stab” switch. Based upon both witness statements and flight data from the Cockpit Voice Data Recorder (CVDR) and Flight Data Recorder (FDR), the Wing Stab ice switch was turned on about 9 minutes after engine start, while the pilot was performing his checklist; however, it was turned off shortly thereafter. The recorded position of the Wing Stab system switch remained off through the remainder of the recorded data. The airplane pilot’s operating handbook (POH) stated that airplane surfaces contaminated by ice, frozen precipitation, or frost must be deiced before departure. The POH also stated that the airplane must be anti-iced when the risk of freezing precipitation exists or is actually taking place. While deicing removes ice, anti-icing protects against additional icing for a certain period of time. The POH further states that the entire wing should be inspected during the pre-takeoff contamination check, not just the leading edge of the wing or wingtips, and that “when inspecting the wing, during the pre-takeoff contamination check, look at the entire upper surface and not only at the leading edge or wing tip. Although the wing tips can be seen from the cockpit, almost the entire wing is visible from a cabin window. Therefore, it is strongly advised that the visual inspection be done by a crew member from the cabin. Additionally, the crew should ask for the assistance of trained and qualified personnel outside the airplane to assist in the pre-takeoff and check to make sure that the tail and fuselage, which are not visible from the cockpit or cabin, are free of any ice contamination.” Furthermore, the before-takeoff checklist included an ice accumulation check, and included guidance that, “aerodynamic surfaces must be confirmed free of all forms of frost, ice, snow and slush prior to entering the takeoff runway or initiating takeoff.” No evidence of the pilot requesting a passenger or vocalizing that he was checking the wings for ice accumulation was heard on the CVR audio. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Although the Wing Stab ice protection switch was found in the on position, recorded data indicated that, after the initial system check, the wing stab ice protection system remained off through the remainder of the recorded data. The panel the switch was mounted to had separated from the instrument panel and had an area of dirt/mud directly below the switch itself. The anti-ice system valves and controller were tested at the respective manufacturers and functioned normally. Accordingly, based on the evidence, the switch was likely moved to the on position during the accident sequence. It could not be determined why the Wing Stab ice protection switch was turned off. At the accident time, and in the 3 hours before the accident, light snow, mist, IFR ceilings, and a temperature of -1°C were reported at the departure airport. Witnesses reported that around the time of the accident light snowfall with freezing mist existed, which would have allowed for accumulation of ice to form on the upper surfaces of the wings, fuselage, and tail surfaces in the 40 minutes between when the airplane exited the hangar and when it took off. Given that the pilot did not obtain any deice or anti-ice services before departure, and the immediate roll to the left as the weight on wheels transitioned from ground to air, the airplane likely had some degree of ice contamination on the upper surfaces of the wings, fuselage, and tail that affected the flight characteristics of the airplane.

Recorded weather data at PVU at 1117 included wind variable at 6 knots, visibility 3 miles, light snow, mist, overcast ceiling at 800 ft, temperature of -1° C (30° F), dew point temperature -1° C (30° F), and an altimeter setting of 29.79 inches of mercury (inHg). Remarks noted the automated station with a precipitation discriminator; that unknown precipitation began at 1103 and ended at 1111; snow ended at 1103 and began again at 1111; the ceiling varied between 600 and 1,100 ft agl; and that a trace of precipitation occurred after 1056. At 1144, recorded weather included wind variable at 6 knots, visibility 3 miles, light snow, mist, overcast ceiling at 800 ft, temperature of -1° C (30° F), dew point temperature -1° C (30° F), and an altimeter setting of 29.79 inHg. Remarks noted the automated station with a precipitation discriminator; that unknown precipitation began at 1103 and ended at 1111; snow ended at 1103 and began again at 1111; the ceiling varied between 700 and 1,200 ft agl; and that a trace of precipitation occurred after 1056. KMTX WSR-88D base reflectivity images for the 0.0° elevation scans initiated at 1136:41 and 1142:18 depicted reflectivity values between 10 and 22 dBZ moving from north to south over PVU at the time of the accident. The Graphical Forecasts for Aviation (GFA) products issued before the accident flight and valid at 1100 included light snow likely (greater than 60 percent chance). The National Weather Service Terminal Aerodrome Forecast (TAF) at PVU, which was issued at 1038, included light snow showers and overcast cloud layers at 1,000 ft around the time of the accident. A search of archived information indicated that the pilot did not request weather information from Leidos Flight Service. He did not receive a weather briefing package from ForeFlight; however, he did view and update several route strings in their ForeFlight application the evening before the accident. The pilot held type ratings for CE-500, CE-525S, and EMB-505 airplanes. His most recent recurrent training in the accident make/model airplane was in May 2022. The airplane was equipped with a Wing and Horizontal Stabilizer Anti-Icing System (locations depicted in figure 1), which was designed to prevent ice formation and remove any ice formed on the leading edges of the wing and the horizontal stabilizer. The system was activated by a 3-position “Wing Stab” switch on the ice protection panel, which is located just below the lower right corner of the left primary flight display. The switch could be placed in 3 different positions: ON (up): activated the wing and the horizontal stabilizer anti-ice systems. OFF (middle): deactivated the wing and the horizontal stabilizer anti-ice systems. ICE SPEED RESET (down): reset the Stall Warning and Protection System (SWPS) to non-icing schedule and removed the SWPS ICE SPEED message. Figure 1: Airframe Ice and Rain Protection System Deice Systems (Source: Phenom 300 Pilot’s Operating Handbook, Volume 1) The airplane’s Pilot’s Operating Handbook, Section 2-15, Cold Weather Operation, DEICING/ANTI-ICING FLUID APPLICATION, stated in part: Airplane surfaces contaminated by ice, frozen precipitation or frost must be deiced before departure. The airplane must be anti-iced when the risk of freezing precipitation exists at dispatch or freezing precipitation is actually taking place. While deicing removes ice, anti-icing protects against additional icing for a certain period of time, called holdover time. A combination of both deicing and anti-icing may be performed based on the judgment of the flight crew and procedures developed by the operator. The choice of the correct method and fluid to be applied must be done according to the weather condition, available equipment, available fluids and the holdover time. Deicing and anti-icing fluids lower the freezing point of frozen precipitation thus delaying the accumulation of contamination on the airplane. When applied to a clean surface, the fluid forms a thin layer that has a lower freezing point than precipitation. The fluid is highly soluble in water, thus the precipitation or ice melts on contact with the fluid. These fluids also delay the onset of frost on airplane surfaces. As the ice melts, the fluid dilutes with the water, thereby causing the mixture to become less effective or to run off. Ice can begin to form again after enough dilution has occurred and the freezing point begins to rise. Deicing/anti-icing fluids are not intended to provide icing protection during flight. The fluid must flow off the surface during takeoff. Embraer has performed flight tests to investigate the effects of approved fluids on performance and handling characteristics. The flight tests demonstrated these fluids did not have a measurable effect on takeoff and climb performance.” The POH continues later in the same section: The pre-takeoff contamination check is normally accomplished either from inside or outside the airplane within 5 minutes prior to beginning takeoff. When inspecting the wing, during the pre-takeoff contamination check, look at the entire upper surface and not only at the leading edge or wing tip. Although the wing tips can be seen from the cockpit, almost the entire wing is visible from a cabin window. Therefore, it is strongly advised that the visual inspection be done by a crew member from the cabin. Additionally, the crew should ask for the assistance of trained and qualified personnel outside the airplane to assist in the pre-takeoff and check to make sure that the tail and fuselage, which are not visible from the cockpit or cabin, are free of any ice contamination. It is the pilot's responsibility to decide whether or not to accept the airplane for flight. If contamination is suspected, the airplane should return for additional deicing or anti-icing. Takeoff in conditions of moderate and heavy freezing rain is not approved. The POH further stated that “to prevent frozen contamination on airplane surfaces deice and anti- icing operation requires that fluids be distributed uniformly over surfaces. In order to control uniformity, all horizontal surfaces must be visually checked during fluid application. The correct amount is indicated by fluid just beginning to drip off the leading edge. Do not use tools to scrape or scratch compacted snow from the airframe surfaces or from the gaps between fixed or movable surfaces. Once the airplane has been fully deiced, it is time to consider the prevention of any further ice contamination prior to takeoff by application of an anti-icing treatment. The following surfaces must be protected: • fuselage; • wing upper surface and leading edge; • horizontal stabilizer upper surface and leading edge; • elevator upper surface; • vertical stabilizer and rudder. Additionally, the airplane’s BEFORE TAKEOFF checklist includes an ice accumulation check and includes the following specific guidance: Aerodynamic surfaces must be confirmed free of all forms of frost, ice, snow and slush prior to entering the takeoff runway or initiating takeoff. This check is particularly important when the published holdover times are about to run out. When contamination is in evidence, the de-icing/anti-icing operation must be repeated. Visually inspect wing surfaces/leading edge and engine by looking through an appropriate window. The pilot-in-command must ask for the assistance of trained and qualified ground personnel to assist in the pre-takeoff check, so that tail surfaces and fuselage are also inspected. The Phenom 300 stall warning system is designed to provide an aural alert at 15.93° local angle of attack (AOA) with a wing flap setting of 1. An autopsy of the pilot was performed by the Utah State Medical Examiner. The cause of death was extensive blunt force injuries, and the manner of death was accident. Toxicology testing p