WPR21FA170

The flight instructor was providing recurrent training to the pilot in the tailwheel-equipped airplane. They had completed several takeoffs and landings at a nearby airport before returning to the departure airport. The first approach to the runway resulted in a go-around due to an unstable approach, and following the second approach, the pilot receiving instruction performed a three-point landing. During the landing roll, the airplane veered left and exited the runway, and the pilot applied full power and “immediately pitched up.” The airplane climbed in ground effect to about 30 ft, then entered a left turn, and its bank angle continued to increase before the airplane impacted terrain. The airplane came to rest adjacent to a hangar in a nose-low, near-vertical attitude. The pilot was fatally injured. The instructor added that, although he had been guarding the flight controls, due to the low altitude of the event, he did not have time to react before impact. Toxicology testing of the pilot receiving instruction detected diphenhydramine, a sedating antihistamine commonly available over the counter in a host of preparations intended to treat cold and allergy symptoms and to induce sleep. The range of levels where effects are expected are above 25 ng/ml, but the drug undergoes significant post-mortem redistribution and levels found in cavity blood likely do not accurately reflect antemortem levels. Although the pilot receiving instruction could have been impaired somewhat by the effects of a small amount of diphenhydramine in his system, some of those effects would have most likely been overcome by the adrenalin naturally produced in the emergency situation. It is therefore unlikely that the small amount of diphenhydramine contributed to the accident circumstances. The accident is consistent with the pilot’s exceedance of the airplane’s critical angle of attack during an aborted landing, which resulted in an aerodynamic stall and impact with terrain.

The FAA publication H-8083-25A, Pilot's Handbook of Aeronautical Knowledge, stated that an aerodynamic stall results from a rapid decrease in lift caused by the separation of airflow from the wing's surface brought on by exceeding the critical angle of attack (AOA). AOA is defined as the acute angle between the chord line of the airfoil and the direction of the relative wind. An aerodynamic stall can occur when the airplane flies too slowly, or when higher wing loads are imposed due to maneuvers such as pull-ups or banked flight. On April 21, 2021, about 1513 Pacific standard time, a Consolidated Vultee BT-13A, N53331, was substantially damaged when it was involved in an accident near Camas, Washington. The pilot receiving instruction was fatally injured and the flight instructor sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The instructor, who was seated in the aft seat, reported that the purpose of the accident flight was to provide recurrent training to the pilot receiving instruction. They departed, flew to a nearby airport, and conducted several takeoffs and landings in the tailwheel-equipped airplane before returning to the departure airport. The instructor stated that the first approach to land on runway 25 resulted in go-around, due to a confusion with the power setting and altitude and airspeed fluctuations to the runway. Following the second approach, the pilot performed a three-point landing, and during the landing roll, the airplane veered left and exited the runway. The instructor stated that the pilot did not attempt to return to the runway, but at an airspeed of about 35 miles per hour, “the pilot added full power and immediately pitched up.” The airplane climbed in ground effect to about 30 ft above the ground, then entered a “stalling left turn.” The instructor stated that the bank angle to the left continued to increase as the nose dropped before the airplane impacted terrain. The instructor further added that he had been guarding the flight controls but because of the low altitude, he did not have time to correct. The instructor reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. An autopsy of the pilot was performed by the Clark County Medical Examiner’s Office in Vancouver, Washington, which listed the cause of death as “multiple blunt force injuries.” Toxicology testing performed at the Federal Aviation Administration Forensic Sciences Laboratory found diphenhydramine at 92 ng/ml in blood, as well as acetaminophen. Both were also identified in urine. Diphenhydramine is a sedating antihistamine commonly available over the counter in a host of preparations intended to treat cold and allergy symptoms, and to induce sleep. The range of levels where effects are expected are above 25 g/ml, but the drug undergoes significant post-mortem redistribution and levels foundin cavity blood likely do not accurately reflect antemortem levels. Acetaminophen, a pain and fever medication commonly known as Tylenol, is not considered impairing. The pilot receiving instruction held a private pilot certificate with an airplane single-engine land rating. At the time of the accident, he had accumulated about 274 total hours of flight experience, of which 177 hours were in the accident airplane from November 2014 to April 2021. He completed about 9 flight hours of dual instruction with a flight instructor in the accident airplane about 6 months before the accident flight. Postaccident examination of the accident site revealed that the airplane impacted terrain about 890 ft from the approach end of runway 25, and 95 ft south of the runway, as seen in figure 1. A damaged runway light was observed about 570 ft from the runway threshold. The first identified point of impact with terrain was a ground impression that was about 6 ft in length and contained red navigation light lens fragments. The debris path was oriented along a 215° magnetic heading and extended about 120 ft from the initial point of impact to the main wreckage. The airplane came to rest in a near-vertical attitude against a hangar on a heading of 141° magnetic. The fuselage and wings remained intact except for the forward portion of the fuselage, which had sustained impact damage; the engine and engine mount separated from the firewall. Flight control continuity was established from both cockpit controls to all primary flight control surfaces. Figure 1: Overview of the accident site