flight 9525 has reignited this debate over cameras inside airplane cockpits. some say it's a good idea. others consider it a violation of pilot privacy. >> reporter: andreas lubitz had locked himself alone in the cockpit as the captain pounded on the door. now, safety experts are calling for a bold move to avoid another disaster. cameras in the cockpit. >> the cameras would not be on the face of either of the pilot or the co-pilot. they would focus on the instruments and on the manipulations that are made. >> reporter: former ntsb chairman jim hall said cameras in the cockpit would be a be deterrent to bad behavior. what could cameras detect? >> you can see the instruments. you can see what they're seeing on the screens. you can see what they're doing with their hands. >> reporter: cameras on the instruments wouldn't necessarily give investigators much help in the germanwings crash probe.