More than 1,000 US Army Corps Engineers personnel have been activated to help clear the critical shipping channel in Baltimore, where the Francis Scott Key bridge collapsed after being hit by a cargo ship. The ship remains stuck within the Port of Baltimore and debris is blocking the busy channel, affecting thousands of workers. Meanwhile, investigations into the cause of the deadly disaster have revealed that one of the ship's pilots radioed for tugboat help, later reporting a loss of power on the vessel, just minutes before it crashed. More data is being reviewed from the ship's black box. Sally Patterson reports from Baltimore.