The pilot and passenger departed a private airport in an experimental amateur-built airplane. A witness who knew the pilot described the pilot as flying “aggressively” and observed the airplane complete a barrel roll, and then enter into an aerodynamic stall and spin into a swamp. The witness also advised that it sounded as if the engine was brought back or went back to idle power. Postaccident examination of the accident site and wreckage revealed that there was no debris path, the wreckage was partially submerged, and the odor of fuel was present, along with a fuel sheen on the surface of the water. Flight control continuity was established. The throttle control was in the closed (idle) position and damage to two of the three propeller blades showed no leading-edge gouges or chordwise scratches that would indicate that the propellers were operating under high power at impact. The third propeller blade was submerged in the swamp and could not be examined. The engine was also submerged in the swamp, was not recovered, and could not be examined. Review of weight and balance information indicated that the airplane was likely being operated in excess of the kit manufacturer’s published gross weight. The weight would have resulted in a higher stalling speed, which would have made the airplane more difficult to control in the barrel roll and more difficult to recover once the stall and spin had begun.The pilot was employed as an airline pilot. He was on medical leave for depression, anxiety, and a head injury. The pilot’s toxicology was positive for ethanol. The consistency of ethanol levels across multiple postmortem specimens, including vitreous fluid, indicated that the pilot likely had consumed ethanol before the accident. Based on the ethanol concentrations he likely experienced degradation of judgment and deficits in coordination, psychomotor skills, Page 2 of 12 ERA22FA422perception, and attention. In addition, the pilot’s toxicology results detected delta-9-THC and its metabolites 11-hydroxy-THC and carboxy-delta-9-THC. Research shows poor and inconsistent correlation between the degree of impairment and delta-9-THC blood levels in living persons. Interpretation of levels in postmortem cavity blood is further complicated by cavity blood’s potential for contamination. Thus, the pilot’s delta-9-THC results could not be used to determine if specific impairing effects were present. In addition, the pilot’s toxicology results detected other central nervous system depressant medications including quetiapine and gabapentin, both of which can adversely interact with one another, in addition to ethanol, to worsen impairment—most commonly in the form of drowsiness, difficulty concentrating, and confusion.  According to the Federal Aviation Administration (FAA) medical case review, the pilot had a significant history of depression and anxiety. Depression can impact risk perception; specifically, some depressed persons will avoid risk to avoid anxiety, while others may engage in risky behavior without consideration of the consequences. One month before the accident, a psychologist assessed the pilot via formal neurocognitive testing and recommended him for consideration of Special Issuance medical certification. The pilot’s psychiatrist assessed the pilot’s condition to be “stable.” Thus, whether the pilot’s psychiatric condition contributed to the accident could not be determined.The pilot’s autopsy detected mild coronary artery disease with low grade stenoses and a flabby myocardium. Due to his mild heart disease, the pilot was at a slightly increased risk of a sudden distracting, impairing, or incapacitating cardiac event, including angina, arrhythmia, or heart attack; however, there is no forensic evidence that such an event occurred. The circumstances of the accident with the pilot actively controlling the airplane through an aerobatic maneuver is generally inconsistent with a sudden incapacitating event. Thus, it is unlikely that the pilot’s heart disease contributed to the accident.In summary, the airplane’s overweight condition, and the pilot’s use of ethanol, delta-9-THC, gabapentin, and quetiapine before the accident, likely contributed to the accident. The contribution of the pilot’s mental health to the accident could not be determined.