Federal investigators say two electrical blackouts, one caused by a loose wire and another by problems with a fuel pump, disabled the controls of a huge cargo ship before it crashed into Baltimore’s Francis Scott Key Bridge, causing it to collapse last year and kill six construction workers. The National Transportation Safety Board held a hearing Tuesday to approve investigators' findings and safety recommendations on the crash. The crew was able to get the power back on after the first blackout, but a second blackout was caused by a lack of fuel because the fuel flushing pump they were using doesn’t restart automatically the way the main pumps are designed to do.