about how crew members can help each other avert disasters? >> reporter: well you touched on it fredricka. you're talking about two-person rule. we've been talking about it with pilot buck rodger. we were in an a-320 simulator this morning. how critical is that two-person rule? >> well the two-person rule really went into effect after 9/11 in the u.s. so we -- tsa has mandated all u.s. carriers to have a two-person rule and what that means is when somebody leaves the cockpit, another crew member comes in so there's always two people in the cockpit. it's for safety. if the pilot were to become incapacitated, the flight attendant would be there to open the door to allow the other crew member back into the cockpit. it's also there to verify who is coming back into the cockpit to make sure that it's the right person. >> reporter: but being alone, this co-pilot was cruising at 38,000. this is what we are at right now. >> we're right now at 38,000 feet. autopilots are all engaged, and this would be a normal cruise