Marengo, WI, USA
N843AC
American Champion Aircraft 8KCAB
The pilot and passenger were conducting a personal flight. The pilot’s sister-in-law received a phone call from the pilot about 5 minutes before the accident, during which the pilot told her to wait outside because he intended to fly over her house. The airplane then overflew her position multiple times at a low altitude before she saw the airplane “doing a loop” shortly before it descended into terrain. Another witness saw the airplane flying “pretty low” about 200 - 400 ft above the ground. The witness stated that the airplane dove toward the ground while flying to the west before it “went back up going upside down” while flying to the south. The airplane then descended and crashed in a residential yard while flying north. Based on video footage, the pilot completed several low passes and steep turns while flying near his sister-in-law’s house; there was no video evidence that the pilot attempted an aerobatic loop maneuver. Further review of on-board video footage indicated the airplane’s bank angle exceeded 80° left-wing-down, and the stall warning horn was audible in the seconds before the accident. Another video, captured by the pilot’s sister-in-law on the ground, showed the airplane in a steep nose-down descent in the moments before the accident. Based on the available information, it is likely that the pilot did not maintain adequate airspeed during a steep turn, which resulted in the airplane exceeding its critical angle of attack and an inadvertent aerodynamic stall at a low altitude. The low altitude at which the aerodynamic stall occurred likely prevented a successful recovery. Postaccident examination of the airplane and engine revealed no evidence of a preexisting mechanical malfunction or failure that would have prevented normal operation of the airplane. Although the pilot’s autopsy revealed he had acute myocarditis, likely due to COVID-19, there was no evidence of impairment based on the on-board video footage. Additionally, toxicological testing did not reveal any impairing substances.
HISTORY OF FLIGHTOn October 23, 2021, about 1440 central daylight time, an American Champion Aircraft 8KCAB airplane, N843AC, was destroyed when it was involved in an accident near Marengo, Wisconsin. The pilot and his passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot’s sister-in-law reported that she received a phone call from the pilot about 5 minutes before the accident, during which the pilot told her to wait outside because he intended to fly over her house. The airplane overflew her position multiple times at a low altitude before she saw the airplane “doing a loop” shortly before she heard the airplane crash. The pilot’s sister-in-law used her mobile phone to capture several “live” photos of the airplane while it maneuvered near her house during the final minutes of the flight. These “live” photos consisted of several frames of video with sound to create a short movie clip. One of these movie clips showed the airplane as it flew over a residential yard at a low altitude, as shown in figure 1. Another movie clip showed the airplane in a steep nose-down descent in the moments before the accident, depicted in figure 2. A review of the sound spectrum extracted from the movie clip that captured the final descent determined the fundamental propeller blade passage was about 80 Hz, which corresponded to 2,400 rpm for the 2-blade propeller installed on the airplane. Figure 1. Airplane flying low over the ground (still image extracted from a video that was recorded by a witness) Figure 2. Airplane descending during final low altitude maneuver (still images extracted from a video that was recorded by a witness) Another witness was driving when he saw the airplane flying “pretty low” about 200 - 400 ft above the ground. The witness stated that the airplane dove toward the ground while flying to the west before it “went back up going upside down” while flying to the south. The airplane then descended and crashed in a residential yard while flying north. A postaccident review of the passenger’s mobile phone determined that it contained a video recording of the flight. The phone, which was hand-held by the passenger who was seated in the rear seat of the airplane, frequently changed its view throughout the recording. However, in general, the camera’s field of view was out of the airplane’s right-and-left rear seat windows. The airplane’s general ground track in the vicinity of the accident location was constructed based on recovered video footage and is depicted in figure 3. The airplane’s bank angle with respect to the visible horizon was estimated for several turns, with each turn chronologically numbered 1 - 6 and annotated in figure 3. Additionally, the airplane’s maximum bank angle during each turn is listed in table 1. Figure 3. The airplane’s estimated ground track in the minutes before the accident, with red numbers indicating where the bank angles were measured during each turn Table 1. Estimated maximum bank angle during turns Based on the passenger’s video recording, the final maneuver began with the airplane rolling into a wings-level attitude before it pitched up into slight climb for about 3 seconds. The pilot then pitched the airplane into a negative G maneuver during which the passenger stated “Whooooa.” About 2 seconds later, the pilot increased airplane pitch into a rapidly positive G maneuver. The pilot then rolled the airplane into a steep (at least 80°) left-wing-down bank before the camera view panned into the interior of the airplane and showed the rear control stick in a neutral roll and slightly nose-up pitch input. About a second later, the rear control stick showed a nose-up pitch input, which was quickly followed by a right roll input in addition to the nose-up pitch input. During the final 3 seconds of the flight, the airplane’s stall warning horn was audible, the passenger was laughing, and the pilot stated an expletive. The pilot maintained the slight nose-up pitch input with a moderate right roll input until the video concluded with the sound of the airplane impacting the ground. There was no video evidence that the passenger interfered with the airplane’s flight controls during the flight. AIRCRAFT INFORMATIONBased on available maintenance documentation, the airframe total time since new was 2,345.9 hours. The factory rebuilt engine and new propeller accumulated 16.9 hours since they were installed on the airplane on September 21, 2021. A review of the maintenance logbooks revealed no unresolved discrepancies or maintenance actions. AIRPORT INFORMATIONBased on available maintenance documentation, the airframe total time since new was 2,345.9 hours. The factory rebuilt engine and new propeller accumulated 16.9 hours since they were installed on the airplane on September 21, 2021. A review of the maintenance logbooks revealed no unresolved discrepancies or maintenance actions. WRECKAGE AND IMPACT INFORMATIONA postaccident examination determined the airplane’s right-wing leading edge impacted the roof of a house before the fuselage impacted the ground in a nose-down pitch attitude. The main wreckage came to rest in the backyard of the house on a north heading. The main wreckage consisted of the fuselage, empennage, engine, and propeller. Both wings separated from the upper fuselage during impact and were found about 20 ft north of the main wreckage. All structural components and flight control surfaces were located at the accident site. Flight control cable continuity could not be established; however, all observed separations were consistent with impact-related damage. The wreckage examination revealed no evidence of a preimpact mechanical malfunction or failure that would have precluded normal operation. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilot was completed at the request of the Dane County Medical Examiner, McFarland, Wisconsin. According to the autopsy report, the pilot died as result of blunt force injuries. From histology sections of the myocardium, the medical examiner reported the pilot had acute myocarditis of probable viral etiology; his postmortem nasopharyngeal swab sample was positive for SARS-CoV-2 RNA (the virus that causes COVID-19). No other significant natural disease was identified. Toxicology testing performed for the medical examiner’s office was positive for caffeine in the pilot’s pleural blood. Federal Aviation Administration toxicology testing did not detect any carboxyhemoglobin, ethanol, or tested-for drugs.
The pilot’s failure to maintain adequate airspeed during the steep turn, which resulted in the airplane exceeding its critical angle of attack and an aerodynamic stall. Also causal was the pilot’s decision to conduct steep turns without sufficient altitude to safely recover from an inadvertent aerodynamic stall.
Source: NTSB Aviation Accident Database
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