WPR24FA014

Two flight instructor-certificated pilots and a passenger on a personal flight departed from an airport in high density-altitude conditions with a slight tailwind. A witness located near the airport reported observing the airplane flying at a low altitude over the trees with its wings wobbling. He stated that the airplane climbed to a maximum altitude of about 100 to 200 ft above ground level (agl) before it began a left turn toward the airport road then fell straight toward the ground. The circumstances of the accident flight, the accident site evidence, and the witness account were consistent with the airplane entering an aerodynamic stall and uncontrolled descent at low altitude. Although the witness reported that he felt certain that he heard the engine shut down about 3 to 5 seconds before impact, propeller damage and propeller strike marks on the ground were evidence of engine power at impact. Further, postaccident examination of the airframe and engine revealed no evidence of mechanical failure or malfunction that would have precluded normal operation. Regardless, based on the witness’s description of the airplane’s wings wobbling in flight, the aerodynamic stall was imminent before the reported change in engine sound, and the pilot flying did not adequately adjust the airplane’s pitch to prevent it. The left-seat pilot’s toxicology results detected isomers of tetrahydrocannabinol (THC) and their metabolites, indicating that he had used one or more cannabis products. Whether the detected delta-9-THC, delta-8-THC, and cannabidiol (CBD) came from the same product or multiple products is unknown. Delta-9-THC and delta-8-THC have potential to cause cognitive and psychomotor impairment. However, the precise timing of the left-seat pilot’s use of these substances and whether the substances were causing significant impairing effects at the time of the accident cannot be determined from the measured levels of the substances and their metabolites. The measured levels of psychoactive substances were relatively low, but this does not exclude associated impairment. The right-seat pilot’s toxicology results indicated that he had used several medications commonly used to treat cold or allergy symptoms. The likelihood of these medications causing significant impairment was low. However, the presence of these medications might indicate a potentially distracting or otherwise impairing condition such as an acute upper respiratory infection or symptomatic seasonal allergies. Whether the right-seat pilot was experiencing such effects from an underlying condition at the time of the accident could not be determined from the available medical evidence. The airplane was equipped with dual flight controls, and both pilots were qualified to fly the airplane. However, based on the available video evidence from previous flights, during which the left-seat pilot was flying the airplane and the right-seat pilot provided comments and suggestions without intervening onthe controls, the left-seat pilot was likely flying the airplane during the accident flight. Video evidence from previous flights indicated that the left-seat pilot had allowed the airplane’s airspeed to decay to the point of stall warning horn activation on three occasions during two previous takeoffs without the passenger on board.

The FAA Safety Team produced a safety enhancement topic on Mountain Flying Tips. The publication included, in part, the following information: o A normally aspirated engine will lose 3% of its power per thousand ft of density altitude increase. o The wings have less dense air with which to create lift. Since a propeller is an airfoil, it, too, will be less efficient. o The aircraft gross weight and its effect on performance should be carefully considered. A minimum of 60 horsepower per occupant should be considered a minimum. o To help regain some of the loss takeoff and landing performance at high density altitudes, you should reduce the weight at which you fly the airplane to no more than 90% of maximum gross weight. The FAA Safety Team produced a safety enhancement topic on Mountain Flying. The briefing included in part: Failure to take density altitude into consideration has led many pilots into situations their aircraft couldn’t handle. It is imperative that you understand how your aircraft performance is affected by density altitude. Even in the early evening, density altitude can be quite high and can present problems if you are not properly trained and prepared. (Note: The following discussion was about the airport and had no direct association with the accident). The Director of Aviation Safety at Embry-Riddle Aeronautical University in Prescott, Arizona, mentioned that CMR was on their dual-only airport lists and that they were working a study of the airfield and drafting performance data and density altitude operations samples for CMR. He stated that, during the summer, they often cannot get a Cessna 172 out of CMR with more than a 50 to 100 ft clearance above terrain on upwind. He further commented that there is a small margin for error to safely land off-airport there. According to the Cherokee PA-28-140 Aircraft Flight Manual’s Climb Performance Chart, for a full-power takeoff (with the mixture leaned per Lycoming instructions) performed at an airplane gross weight of 2,150 lbs with a 0° flap setting at 89 mph calibrated airspeed, the climb performance in the calculated density altitude at CMR at the time of the accident would be about 200 ft per minute. The airplane’s maximum takeoff gross weight was 2,150 lbs. Weight and balance calculations revealed that, at a standard fuel load of 36 gallons, the airplane’s gross weight would be about 2,150 lbs and the within center of gravity limits. At a full fuel load of 50 gallons, the airplane would be over its maximum gross weight limit. The publicly owned, nontowered airport had an elevation of 6,691 ft. Runway 18 had a 1.0° uphill gradient. High terrain surrounded the airport to the south and east. The airplane was not equipped or required to be equipped with any onboard flight recorder. As stated in “History of Flight,” videos recovered from the left-seat pilot’s two PEDs provided information about some of the flight legs conducted the day before the accident, including the following:o During the approach to SGU, the two pilots discussed where to touch down when landing behind a heavier aircraft, with one pilot correcting the other’s mistaken statement that they should land before the touchdown point of the heavier aircraft. o During the landing roll at SGU, the left-seat pilot nearly lost control of the airplane during a high-speed exit from the runway, then the two pilots discussed how to navigate around a closed taxiway. o While at 1L8, the right-seat pilot corrected the left-seat pilot regarding the airplane’s final approach and takeoff rotation airspeeds and corrected the left-seat pilot’s mistaken statement that he would use Vy (best rate of climb airspeed) to clear some powerlines, reminding him to use Vx (best angle of climb airspeed) instead. o During approaches to L41 and U55, the right-seat pilot questioned the left-seat pilot about his execution of tight, nonstandard traffic patterns. The left-seat pilot landed the airplane at least halfway down the runway at L41, and overshot the centerline at U55, correcting back sharply at low altitude to perform a touch-and-go landing. o During departure from L41, the left-seat pilot used two notches of flaps to perform a short-field takeoff technique. When he brought up the last notch of flaps, the airplane’s stall warning horn activated. o During departure following a touch-and-go landing at BCE, the left-seat pilot remarked that he was using two notches of flaps. When the left-seat pilot reduced the flap setting, the stall warning horn activated. The left-seat pilot made a right turnout, the right-seat pilot stated, “keep climbing,” and the left-seat pilot stated, “I want to climb, this guy’s not climbing.” The stall warning horn again activated then turned off. About 6 minutes later during flight, the left-seat pilot stuck a phone out of the left side small vent window; it appeared the right-seat pilot was flying at this time. On October 17, 2023, about 1219 mountain standard time, a Piper PA-28-140 airplane, N6192J, was substantially damaged when it was involved in an accident near H. A. Clark Memorial Field Airport (CMR), Williams, Arizona. The two flight instructor-certificated pilots and the passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to information recovered from the pilots’ personal electronic devices (PEDs), the accident occurred on the third day of a multi-leg trip in the accident airplane. The pilots obtained the accident airplane on October 15, 2023, at Brown Field Municipal Airport (SDM), San Diego, California, and booked an airplane parking space for that evening through October 18, 2023, at North Las Vegas Airport (VGT), Las Vegas, Nevada. The pilots flew the airplane from SDM to VGT that evening. On October 16, 2023, the pilots flew the airplane from about 1000 to 2000 with stops at St. George Regional Airport (SGU), St George, Utah; Hurricane Municipal Airport (1L8),Hurricane, Utah; Marble Canyon Airport (L41), Marble Canyon, Arizona; and Page Municipal Airport (PGA), Page, Arizona; with subsequent touch-and-go landings performed at Panguitch Municipal Airport (U55), Panguitch, Utah; and Bryce Canyon Airport (BCE), Bryce Canyon, Utah. The right-seat pilot’s PED contained flight planning information that included these flight legs (as entered into a flight planning application) and showed a planned return to VGT that same day. The left-seat pilot’s two PEDs contained several videos from these flight legs, including two videos that captured audio of the airplane’s stall warning horn activating during the left-seat pilot’s climb after takeoff from L41 and BCE, and one video that captured the left-seat pilot’s climb after takeoff from U55, during which he stated that the airplane “had little hard time climbing” due to the local high altitude. (See the “Flight Recorders” section below for more information.) The right-seat pilot’s PED contained a message exchange with the passenger on October 16, 2023, discussing a plan for the passenger to take flights with the pilots the next day. On October 17, 2023, the passenger joined the two pilots at VGT. A fuel receipt showed that 22.4 gallons of fuel were added to the airplane before the airplane departed on the first flight leg (the flight leg before the accident flight) about 0930. Videos recovered from the left-seat pilot’s PEDs showed the airplane in flight in the vicinity of Grand Canyon National Park Airport (GCN), Grand Canyon, Arizona, about 1038, then on approach into CMR about 1143. The airplane landed at CMR about 1150, and the pilots added about 20 gallons of fuel to the airplane. The accident occurred about 30 minutes later, shortly after takeoff from runway 18 at CMR. The pilots’ PEDs contained no photos or videos of the accident flight. A witness who lived near the airport reported observing the airplane flying at a low altitude over the trees with its wings wobbling. He stated that he had seen enough airplanes coming in and out of the airport to notice that the wobbling wings did not appear normal. He observed the airplane climb to a maximum altitude of about 100 to 200 ft agl before it began a left turn toward the airport road. He stated that he was “100% certain” that the airplane’s engine shut off before the airplane fell straight toward the ground. An autopsy of the left-seat pilot was performed by the Coconino County Medical Examiner’s Office in Flagstaff, Arizona. According to the autopsy report, the cause of death was multiple blunt force injuries. Toxicology testing performed at the FAA Forensic Sciences Laboratory detected the following in specimens from the left-seat pilot: Delta-9-THC, Delta-8-THC, CBD, and their respective metabolites. Delta-9-THC is the primary psychoactive chemical in cannabis, including marijuana, hashish, and cannabis edibles. The presence of Delta-9-THC and its metabolite, carboxy-delta-9-TCH, has usually been consideredindicators of marijuana use; however, it has been much debated whether CBD can produce delta-9-THC and carboxy-delta-9-THC as metabolites. The most recent research suggests that this does not happen and that the presence of THC compounds indicates marijuana use. However, CBD produced from natural sources may be contaminated with low levels of THC. The instantaneous level of delta-9-THC in a living person’s blood does not directly predict impairing effects, and interpretation of postmortem levels of delta-9-THC in cavity blood is further complicated by the fact that such levels may differ from antemortem levels. Marijuana is a federal Schedule I controlled substance, and the FAA considers its use by pilots unacceptable, regardless of state laws. Delta-8-THC is less potent than delta-9-THC but can still produce a “high.” It is found in marijuana and hemp at low concentrations and is available as a synthetic CBD. Delta-8 THC products are marketed with a variety of claims but have not been evaluated or approved by the United States Food and Drug Administration for safe use in any context and may contain contaminants, including delta-9-THC. An autopsy of the right-seat pilot was performed by the Coconino County Medical Examiner’s Office in Flagstaff, Arizona. According to the autopsy report, the cause of death was multiple blunt force injuries. Toxicology testing performed at the FAA Forensic Sciences Laboratory detected the following in specimens from the right-seat pilot: Loratadine and its metabolite desloratadine, pseudoephedrine, dextromethorphan, and its metabolite dextrorphan. Loratadine (Claritin) is a non-sedating antihistamine medication used to treat allergies. Loratadine is available in over-the-counter (OTC) medications acceptable for pilots. Pseudoephedrine was detected. Pseudoephedrine (Sudafed) is an OTC decongestant used to treat nasal congestion and is acceptable for pilots. Pseudoephedrine is also available compounded with loratadine as Claritin-D. This medication is acceptable for pilots. Dextromethorphan is used as a cough suppressant and can cause drowsiness and nausea. Dextromethorphan is disqualifying for flying and requires at least 48 hours before performing pilot duties. Based on the reported weather conditions at the time of the accident, the calculated density altitude was about 8,922 ft. In addition, the reported wind was about 280° at 6 knots with gusts to 12 knots. The winds would make for a moderate crosswind from the west and a slight tailwind of about 1 to 2 knots for takeoff from runway 18. The airplane came to rest inverted about 1/2 mile south of the runway 36 threshold on a heading of about 129°. The terrain was located about 6,670 ft in elevation and was flat and rocky with sage brush vegetation. A ground disturbance was observed at the initial impact point that was about 6 inches wide and 1 ft long with the debris field scattered along a bearing of about 171°. Fragments of red lens, consistent with the leftwing position light, were located in the disturbance; additional ground disturbances and propeller strikes onto the ground were observed extending from the initial impact point to the airplane wreckage. All major components of the airplane were contained within the main wreckage site. The flap handle, flap torque tube, and right flap were found in the retracted position. The propeller remained attached to the crankshaft propeller flange. The propeller flange sustained damage and deformation. One propeller blade was bent forward about mid-span, and the other blade was slightly twisted. Some chordwise marks were observed on both blades. The spinner was attached and was crushed. Postaccident examination of the airframe and engine revealed no evidence of preimpact failure or malfunction that would have precluded normal operation of the airplane.