Airframe - Other involving De Havilland DHC2-FP, VH-AQA, Palm Beach, New South Wales, on 18 November 1990

Circumstances:

The floatplane was taking off towards the south into a wind reported as south-east to south gusting to 30 kt. Water conditions were described as choppy. After a run of about 300 m, just prior to the aircraft becoming airborne, the pilot reported hearing a loud bang. The aircraft immediately commenced a sharp left turn, followed by several rocking oscillations. The pilot shut down the engine after which the aircraft slowed and stopped in a left wing low attitude with the wingtip in the water. The front landing wire attachment bracket on the left float and the aft landing wire attachment bracket at the top of the rear right strut had both failed at their respective bolt holes. Metallurgical examination found that both brackets were extensively corroded, with the bracket cross sections being reduced by about 30 percent in both cases. It was considered that the reduced cross-sectional area was insufficient to sustain normal applied loads. It appeared that the front left float bracket failed first, followed by the rear right strut bracket, resulting in pivotal movement of the left float.

Significant Factors:

The following factors were considered relevant to the development of the accident

1. Inadequate inspection.

2. Extensive corrosion of landing wire attachment brackets.

3. The weakened brackets failed under the operating conditions prevailing.