On June 18, 2024, about 1400 Alaska daylight time, a float-equipped Piper PA-18-150 airplane, N645DT, was substantially damaged when it was involved in an accident near Moose Pass, Alaska. The instructor pilot and the pilot receiving instruction were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the operator, Alaska Float Ratings, the pilot receiving instruction, seated in the front seat, and the instructor pilot, seated in the rear seat, departed Trail Lake, Moose Pass, about 1245, with an anticipated return time of no later than 1430. When the airplane failed to return, the operator initiated a search for the overdue airplane, and found portions of floating wreckage on Crescent Lake. Search personnel from the Alaska State Troopers and Alaska Air National Guard, along with several volunteers, were dispatched to conduct an extensive search of the area, and the shoreline. The operator reported that the purpose of the flight was to provide the pilot receiving instruction with dual flight training as part of a single engine sea add-on rating. The operator added that at the time of departure, the planned destination was Bench Lake, and the airplane departed with 25 gallons of 100LL aviation fuel onboard. Two witnesses, located at the northeast shoreline of Crescent Lake, reported passively watching the accident airplane perform several touch-and-go landings near the middle of the lake. They said that as the airplane continued a northeasterly approach for another touch-and-go, at an estimated 400 ft above the water, their attention was drawn to the airplane after it pitched down in a nose low attitude, and as it began a slight counterclockwise rotation before impacting the water. One witness recalled seeing the airplane pitch up slightly just before impact. Shortly after impact, the airplane wreckage sank below the surface of the lake. On June 19, members from the Alaska Air National Guard, Alaska Army Guard, and Alaska State Troopers traveled to Crescent Lake to conduct an underwater search for the airplane wreckage using a remotely operated vehicle (ROV). The team subsequently located the submerged wreckage at 194 ft below the surface. Underwater ROV footage revealed that the left float was liberated from the airplane. The left wing exhibited damage to the inboard leading edge consistent with impact from the left float. On June 20, the recovery teams, along with deep water divers from the Alaska Dive Search Rescue and Recovery Team, returned to Crescent Lake and recovered the submerged airplane wreckage from the bottom of the lake, along with the two occupants, then moved it to the shoreline. The wreckage has been recovered to a secure facility for a detailed examination, which is pending.