CNN The Situation Room May 6, 2015 21:32:00
Stabilized at 25,000 feet. the flight never left its scheduled path so air traffic control didn't notice the altitude changes. >> unless the plane is equipped to stream the data and they decide to stream the data of the aircraft performance from the flight and someone's monitoring it they wouldn't have noticed. and it was clear that the pilot didn't notice for another reason the front lab was inoperative. >> reporter: it appears it was a dry run for what he would do later that same morning on board the very same plane during flight 9525. lubitz waited until the captain left the cockpit, locked...
Source: archive.org