What happened
The incident occurred at the conclusion of a fishing trip involving the pilot and two passengers. The group was preparing to depart from a remote river using a float-equipped airplane. As part of the pre-takeoff routine, the pilot executed a step taxi maneuver to gain speed on the water surface.
During this phase of the operation, low light conditions combined with shadows on the water created significant visual challenges. These environmental factors obscured a small sandbar located in the aircraft's path. The pilot did not detect the obstruction until it was too late to avoid contact.
The floats of the airplane struck the submerged sandbar. The impact caused the nose of the aircraft to pitch downward, resulting in the plane nosing over on the river surface.