CEN23FA270

The pilot’s failure to maintain clearance from the water while flying at a low altitude.

The flight of two airplanes was in cruise flight on a north heading about 50 ft above a lake when the pilots agreed to fly closer to the west shore of the lake. The pilot of the second (non-accident) airplane initiated a climb and turned toward the west. In his peripheral vision, he noticed a splash and thought the pilot of the amphibious light sport airplane had landed on the water. He made several radio calls to the accident pilot with no response. A witness reported seeing both airplanes fly about 30–40 ft above the surface of the water; however, they did not see the accident. The airplane was destroyed when it impacted the water and became submerged in about 26 ft of water. Examination of the wreckage indicated that the airplane impacted water in a left-wing-low attitude. Further examination revealed no evidence of preimpact failures or malfunctions that would have precluded normal operation. Damage to the propeller indicated that the engine was likely under power at the time of the accident. The pilot’s autopsy revealed cardiovascular disease that would have increased his risk of experiencing a sudden impairing or incapacitating cardiac event, such as arrhythmia, chest pain, or heart attack. There was no autopsy evidence that such an event occurred; however, such an event does not leave reliable autopsy evidence if it occurs shortly before death. Toxicology results indicated that the pilot had used a cannabis product. However, the precise timing of his last cannabis use, and whether it caused significant impairing effects at the time of the accident, could not be determined from the measured levels of delta-9-THC and its metabolites.

A witness who was on a boat on Mille Lacs Lake at the time of the accident reported that the water surface had a “very slight chop.” The pilot in the second airplane reported that there were four-to-six-inch waves on the water. The two-seat, high-wing, retractable gear, amphibious light sport airplane was equipped with a ballistic recovery parachute. A special airworthiness certificate was issued for the airplane on May 24, 2019, and the pilot purchased the airplane May 31, 2019. The airplane’s wingspan is 34.8 ft. An autopsy of the pilot was performed by the Mille Lacs County Coroner. According to the pilot’s autopsy report, his cause of death was drowning, and the manner of death was accident. The autopsy identified coronary artery disease, including 70% narrowing of the proximal right coronary artery and 50% narrowing of the mid left anterior descending coronary artery by plaque. Diffuse aortic plaque was also present. The remainder of the autopsy, including visual examination of the heart, did not identify other significant natural disease. Postmortem toxicological testing by NMS Labs detected delta-9-tetrahydrocannabinol (delta-9-THC) at 1 ng/mL in femoral blood. Postmortem toxicological testing by the FAA Forensic Sciences Laboratory detected delta-9-THC in urine and at 1.4 ng/mL in femoral blood. 11-hydroxy-THC was detected at 16.7 ng/mL in urine and was not detected in blood. Carboxy-delta-9-THC was detected at 145.7 ng/mL in urine and at 3.1 ng/mL in femoral blood. Additionally, pseudoephedrine and fexofenadine were found in the pilot's blood and urine. Pseudoephedrine (Sudafed) is an over-the-counter decongestant used to treat nasal congestion and is acceptable for pilots. Fexofenadine (Allegra) is a non-prescription, non-sedating antihistamine used to treat seasonal allergies and is acceptable for pilots. Delta-9-THC is the primary psychoactive chemical in cannabis, including marijuana, hashish, and cannabis edibles. 11-hydroxy-THC and carboxy-delta-9-THC are metabolites of delta-9-THC. Delta-9-THC may be inhaled or ingested recreationally by users seeking mind-altering effects. It may also be used medicinally, such as to treat illness-associated nausea and appetite loss. It rapidly leaves the blood, even during smoking, falling to below detectable levels within several hours. Delta-9-carboxy-THC (THCC) is the inactive metabolite of THC and may be detected for up to one day or more in blood. Both delta-9-THC and THCC may be present substantially longer in chronic users. Psychoactive effects of delta-9-THC vary depending on the user, dose, and route of administration, and may impair motor coordination, reaction time, decision making, problem solving, and vigilance. 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 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. The airplane was highly fragmented, and the main wreckage was submerged in about 26 ft of water. A debris field was scattered on the surface of the water. All flight control surfaces, the engine, and the majority of the airframe were recovered. Both wings remained attached to the engine mount and center wing section. The outboard portion of the left wing was highly fragmented. Portions of the left wing were recovered in the debris field. The left and right ailerons were impact separated. The left aileron pushrod was damaged, but continuous to the bellcrank. The pushrod in the right wing from the wing to center section juncture to the outer bellcrank was intact. The left and right flaps remained attached to the wings at the hinges. The left flap pushrod remained intact but was separated from the forward spar attachment point, consistent with impact damage. The right flap push rod was impact separated from the control surface. The flap switch was found in the 0° position. Both folding wing lock mechanisms were in the "locked" position (the normal position for flight). The empennage was impact separated from the fuselage. The elevator push tube was damaged but remained connected from the bellcrank to the control surface. The rudder cable remained attached to the rudder control surface. The rudder control cable forward of the control surface was fracture separated consistent with overload. Control continuity from the cabin to the rudder and elevator could not be determined due to impact damage. Both left and right folding elevator tips were in the "locked" position (in the normal position for flight). The main landing gear assembly was impact separated and located with the main wreckage. The nose landing gear was impact separated and located with the main wreckage. The landing gear position could not be determined due to impact damage. The landing gear selector was found in the UP position. The engine remained attached to the mount and was recovered with the main wreckage. The top spark plugs were removed and exhibited normal signatures. The oil tank contained oil and water. Water was purged from the cylinders and thumb compression was confirmed on all cylinders. The valve cover on cylinder No. 1 was removed and no anomalies were detected when the propeller was turned by hand. The carbon fiber propeller blades were connected at the hub; however, the blade tips were impact separated. On June 30, 2023, about 1349 central daylight time, an Icon A5 airplane, N239BA, was destroyed when it was involved in an accident on Mille Lacs Lake near Onamia, Minnesota. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to ADS-B data, the airplane originated from the Anoka County/Blaine Airport (ANE), Blaine, Minnesota, about 1300, and proceeded on a northerly course. The accident airplane climbed to about 2,500 ft above mean sea level (msl). The pilot of a second airplane, N268BA, reported that he joined up with the accident airplane about 1315 near Cambridge, Minnesota, for a pre-arranged formation flight. The flight of two then continued on a northwest course and at 1325 climbed to about 6,000 ft msl. Both flights then descended about 16 miles from the south shore of Mille Lacs Lake. The ADS-B data ended at 1347, about 6 miles from the accident site, and showed the accident airplane about 2,200 ft msl at the south shore of Mille Lacs Lake. According to the pilot of the second airplane, both pilots descended over the lake to about 50 to 75 ft above the surface of the water, with the accident airplane “a bit lower.” Both pilots were communicating with each other through onboard radios. The accident pilot’s son was driving on a road on the west shore of the lake communicating to the accident pilot via cellular telephone. The pilots agreed to fly closer to the west shore of the lake. The pilot of the second airplane initiated a climb and turned toward the west. In his peripheral vision, he noticed a splash and thought the accident pilot had landed. He made several radio calls to the accident pilot with no response. A witness reported seeing both airplanes fly about 30–40 ft above the surface of the water; however, they did not see the accident. The accident airplane impacted the water about a mile north of Indian Point in Shah-bush-kung Bay in Mille Lacs Lake. The airplane was equipped with an ICON digital to analogue converter (DAC) that recorded data. The DAC recorded engine parameters, electrical system parameters, discrete states, airspeed, angle of attack, and aircraft load factor, along with GPS information including altitude. In all, there were 369 individual parameters recorded, some of which were duplicates. There was no flight attitude information such as pitch or roll recorded. A review