CEN24FA148

The private pilot and two passengers departed in the experimental airplane into day visual flight rules conditions for a local personal flight. A witness reported that the airplane departed to the south, and that the takeoff seemed routine and there were no obvious anomalies with the airplane. About 15 to 20 minutes later, local authorities received a report of an explosion. Upon arriving at the site, first responders observed the airplane with an active fire. There were no known witnesses to the accident itself, and no ADS-B data related to the accident flight was located. The airplane came to rest adjacent to a large tree about 1.4 miles south-southwest of the departure airport. A post-impact fire consumed portions of the fuselage and charred the large tree and low brush in the surrounding area. The airplane exhibited impact and postimpact fire damage. Portions of the fuselage and both wings were consumed by fire. Flight control continuity was confirmed from each control surface to the cockpit area. The engine was separated from the airframe and rested inverted on the ground near the fuselage. An examination did not identify any anomalies attributable to a preimpact failure or malfunction. The propeller was consumed by the postimpact fire; however, the retaining plates and propeller attachment bolts were intact. No evidence of an in-flight failure or separation of the propeller was observed. Although the extent of the postimpact fire limited the scope of the wreckage examinations, no evidence of an in-flight structural failure, flight control system anomaly, or inability of the engine and propeller to provide rated thrust were observed. The pilot’s coronary artery disease was associated with increased risk of an impairing or incapacitating cardiovascular event; however, there was no autopsy evidence that such an event had occurred. The pilot’s postmortem toxicology results indicated use of the sedating antihistamine medication diphenhydramine, but the level in his postmortem heart blood was low. Detected norchlorcyclizine indicated the pilot also likely used another antihistamine medication long enough before the accident that the medication itself was no longer detectable in his blood. Based on these results, there was no evidence that the pilot was experiencing any significant impairing effects at the time of the accident.

The previous owner of the airplane reported that the airplane’s handling qualities were excellent, noting that it was difficult to aerodynamically stall under normal conditions. The previous owner checked out the accident pilot when he bought the airplane and commented that he was “very good at low-speed maneuvering.” During that checkout flight, the pilot inadvertently turned off the fuel valve with his foot while they were on the ground. The previous owner reported that the airplane was comparable to a Cessna 150 but with better handling qualities. The airplane was placarded for 1,200 lbs maximum gross weight. The previous owner recommended not putting a third person in the airplane because it was underpowered. Maintenance records for the airplane were not available for review. On April 4, 2024, about 1633 central daylight time, a Davis DA-3 airplane, N88DT, was destroyed when it was involved in an accident near Antlers, Oklahoma. The pilot and two passengers were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. A witness reported having a brief conversation with the pilot between 1530 and 1600 at the Stan Stamper Municipal Airport (HHW), Hugo, Oklahoma. Afterward, the pilot departed in the accident airplane. The airplane seemed to perform normally, and nothing seemed out of the ordinary. A second witness observed the airplane arriving at the Antlers Municipal Airport (80F) between 1600 and 1630. Two men met the pilot, and they all boarded the airplane. The pilot subsequently departed toward the south. The takeoff seemed to be routine and there were no obvious anomalies with respect to the airplane. At 1633, local authorities received a report of an explosion. Upon arriving at the site, first responders observed the crashed airplane with an active fire. There were no known witnesses to the accident itself, and no ADS-B data related to the accident flight was located. The airplane came to rest adjacent to a large tree about 1.4 miles south-southwest of 80F. Multiple smaller trees and low brush were also present at the site. A post-impact fire consumed portions of the fuselage and charred the large tree. Low brush was burned over a large area surrounding the airplane. The Office of the Chief Medical Examiner in Tulsa, Oklahoma, performed an autopsy of the pilot. The cause of death was attributed to multiple blunt force injuries sustained in the accident. The autopsy noted the presence of coronary artery disease including approximately 60-70% narrowing of the right coronary artery and 10-20% narrowing of the left anterior descending coronary artery by plaque. Visual examination of the heart did not identify other significant disease. Toxicology testing was performed at the FAA Forensic Sciences Laboratory. Diphenhydramine was detected in heart blood and in liver tissue; however, no specific levels were reported. Norchlorcyclizine was detected at a low level in heart blood and at 53 ng/gin liver tissue. Diphenhydramine is a sedating antihistamine medication widely available over the counter in multiple sleep aids and cold and allergy products. Diphenhydramine can cause cognitive and psychomotor slowing and drowsiness, and often carries a warning about driving and operating machinery. Diphenhydramine has significant potential for postmortem redistribution. Norchlorcyclizine is a metabolite of the antihistamine medications chlorcyclizine, hydroxyzine, and meclizine, and may be an impurity in some formulations of the antihistamine medication cetirizine. Although those medications may have sedating or impairing effects, none of those medications were detected in this case. Norchlorcyclizine itself has not been established to have impairing effects. The pilot’s logbook was not available for review. He reported 112 hours total flight experience at the time of his most recent medical certificate application in January 2022. He was issued a third-class airman medical certificate without limitations at that time. That medical certificate expired on January 31, 2024, and no subsequent medical certificate applications were on file. The pilot did not hold a valid medical certificate or BasicMed certification at the time of the accident. The airplane exhibited impact and postimpact fire damage. The forward section of the fuselage and portions of both wings were consumed. Both wings were separated near the wing roots and rested adjacent to the fuselage. The fracture surfaces appeared consistent with overstress. The flight controls remained attached to the airframe, and control continuity was confirmed from each control surface to the cockpit area. The engine was separated from the airframe and rested inverted on the ground near the fuselage. It exhibited localized impact damage. The entire engine was discolored, and an area of the accessory case was consumed, consistent with the postimpact fire. An on-scene examination, which included borescope examination of the cylinders, did not identify any anomalies consistent with a preimpact failure or malfunction; however, the examination was limited by the extent of the fire damage. The propeller shaft extension from the propeller to the engine was intact, and the bolts were secure and safety wire was properly installed. The propeller was not observed; however, the retaining plates and propeller attachment bolts appeared to be intact and undamaged.