CNN CNN Tonight May 19, 2015 02:30:00
David soucie cnn safety analyst and j.p. wright, co-chair of railroad workers nitds. david, first, the review of the black boxes are complete. what are investigators looking for? >> they're looking to make sure that what was intended to happen is what happened by the engineer for example, if he pushed the throttles forward, did they go forward. if he tried to bring them back did they go back? that will be key in the investigation. >> when i spoke to a member of the ntsb last week i said, is it as easy as a gps, tells you which button was pressed when. he said it wasn't quite that simple but to...