Flight Operations
The aircraft was scheduled to conduct three round trips between Townsville and Cape Richards during the day, with stops at Orpheus Island on some legs. Two pilots operated the flights; one pilot flew the first and third trips, while another pilot flew the second. After the first trip, the pilot reported pumping the floats and considered the quantity of water removed to be normal. On the third trip, a standby passenger was picked up at Orpheus Island.
Loading and Float Condition
Upon arrival at Cape Richards, six scheduled passengers were loaded. A witness employed by the resort to handle the aircraft and passengers reported that the floats appeared to be sitting in the water such that the water was above the normal water line on the floats. Examination of the aircraft loading indicated that the aircraft was overweight, and the center of gravity was just inside the rear limit.
Takeoff Attempts
The pilot reported taxiing at 1613 hours with eight persons on board. At 1624 hours, he reported that he was returning to unload one passenger. In that time, two takeoff attempts into the northeast were made. The wind in the bay where the attempts were made was a light northerly. The pilot again reported taxiing at 1634 hours with seven persons on board, and two further takeoff attempts were made. On the final attempt, the pilot did not taxi as far into the bay as on previous occasions. The takeoff was continued well out beyond the shelter of the island into an area where the wind was easterly at about 10 knots and the swell was 1 to 1.5 meters.
Accident Sequence
The pilot reported that the aircraft had attained an indicated airspeed of 55 knots, and he intended to fly it off the water at 57 knots. The right float had lifted from the water and hit a wave, which pushed the right wing up. The pilot was unable to lift the left wing, which hit the water, causing the aircraft to cartwheel.