is the wreckage of the seaplane. it still lies at the bottom of the hawkesbury river. the authorities hope to bring it to the surface by the end of the week. after it's recovered, the single—engine aircraft will be taken to canberra for examination. we will be looking at a number of areas, particularly around the aircraft's components. we will be removing those and examining them. we will also be looking at any recorder data that might be on the aircraft, so that would involve both avionics or instruments attached to the aeroplane. aviation experts have speculated that the seaplane may have stalled before crashing because of engine failure, an unexpected gust of wind or a mistake by the pilot. a preliminary report from the australian transport safety bureau is expected within a month, but a more comprehensive review of the disaster could take a lot longer. phil mercer, bbc news, sydney.