Rehearsed crash on outbound flight
Investigators say Lubitz practiced entering the fatal descent settings on the previous, outbound flight. The changes in autopilot settings, mimicking those which, two hours later, crashed the jet on its way back to Duesseldorf from Barcelona, would barely have been noticeable because the jet was already descending. Investigator:
I can’t speculate on what was happening inside his head; all I can say is that he changed this button to the minimum setting of 100 feet and he did it several times.