The Capt while passing through 4700ft to 3000ftaccidentally engaged EXPED and he wanted to cancel it. The irony is, first he didn't have to because ALT* would have engaged in perhaps 30secs. automatically cancelling it. OK he wanted to cancel it by pushing EXPED again but that is the only action that wasn't going to do it. Any other action on FCU(except HDG) pull speed/pull or push ALT/push or pull VS would have done it but he by mistake he went for ATHR. Then ID button and hell brakes loose. ATSB report is an exercise in being politically correct. The only reason for the incident is insufficient or half knowledge of EXPED function. Had he known how to come out, it wouldn't have happened. But ATSB runs the whole gamut of human factors, ergonomics but not the real cause. The important lesson always read before pulling or pushing.[/QUOTE]
Actually I was wrong about the details of the incidence. It was even more totally uncalled for. The Capt pressed EXPED descending to 3000ft passing 3600ft. AP was on and ALT* happened immediately and aircraft levelled off. So all was fine. The Pilot didn't seem to have noticed ALT on the FMA and pressed EXPED to cancel it which was wrong for three reasons, first it's not designed that way, second EXPED had already changed to ALT, third there was no target altitude to either activate EXPED. OK! He made another mistake and pressed ATHR instead. But that wouldn't change anything just reengage on the FCU. But now he makes the real mistake of unnecessarily clicking off AP and ATHR. This Click, click could have taken their life.
Last edited by vilas; 25th May 2021 at 12:56.