reporting. one thing to imagine what went on inside that cockpit. it is another thing entirely to be inside a cockpit like 9525 and to see it especially if you're a seasoned aviator like the one our kyung lah introduces to us to tonight. >> reporter: he cannot imagine why a pilot would do this. but foresight knows how. a retired military commercial pilot, said he's flown thousands of hours in the a320 cockpit. one of the safest high-tech passenger jets used around the world. normal? >> lock and unlock. >> reporter: he like all pilots used the switch hundreds of times. >> tun lock, you have to pull up and hold it. light comes on, said the door's open but if i unleash it, goes back. >> reporter: norm means it's locked. >> correct. >> reporter: according to airbus operations video, there's a key pad entry on the outside that allows entry if you know the code.