Australia mourns U.S. firefighters as probe into plane crash begins

MELBOURNE/SYDNEY (Reuters) - Firefighters in Australia held a minute's silence on Friday for three U.S. colleagues killed in a plane crash as investigators scoured the accident site in remote bushland.Flags on official buildings in New South Wales (NSW) state, where the C-130 Hercules crashed while on a mission to dump retardant on a huge wildfire, were flown at half-mast as a mark of respect."We will forever be indebted to the enormous contribution and indeed the ultimate sacrifice that's been