Airbus mode change call outs

[Mr Optimistic]

Just curious given the discussion on R&N about the Malaysian stuff up, when an Airbus automatically degrades to Alt law, do the SOP's require any verbal acknowledgement between the crew? Seems like it can go unnoticed under pressure.

[AerocatS2A]

I don't fly Airbus, but the thing with mode callouts is if you don't notice the mode change, you won't call it (obviously). It is most useful, in my opinion, when making mode changes as it forces you, or should force you, to look at the PFD or whatever your modes are annunciated on, and confirm the change then call it. But if a mode has changed automatically and neither pilot realises, then mode change callout SOPs won't help. In other words, it works as long as at least one pilot is "in the loop" and it helps bring the other pilot into the loop.

[Mr Optimistic]

Thanks. There is the opposite point though: if call out and acknowledgement were mandated, then the absence of that on CVR would indicate that it has been overlooked. AF447 and now Indonesia... such an important change perhaps needs clearer annunciation?
This is assuming it already isn't required of course.

[PAXboy]

(Pax speaking) With such a crucial moment as mode change, might the a/c not 'call out' itself? In the same way that it calls out other critical things to do with GPWS, height calls and 'Retard' - it could call the change and require action by the crew to ack?

I appreciate that there are many, many indicators and call outs on the flight deck but such a critical change might deserve it's own.

[Mr Optimistic]

Trouble is the Indonesian incident looks like the capt went off piste and carefully pulled CB's on two computers one at a time probably thinking that one was always available. He forgot the need to toggle on/off buttons presumably. Perhaps indicates he was aware that two off equalled switch to alternate but was confident he avoided it so not the focus of immediate attention given the roll surprise.

Aural presumably wouldn't get attention so something BIG which needs crew interaction to acknowledge? Don't recall the mode degradation called out on the AF447 transcript. Two very similar sequences would seem to indicate that the human computer interface is not great at convincing of stall or off impressing that the mode had degraded.

Seems that there is no standard procedure for voicing acknowledgement of mode change - my original question, which to my pax eyes seems underplaying it a bit.

[Double Hydco]

I do fly Airbus.

If it goes into ALTN LAW you'll know about it. It gives you an ECAM warning for one thing. Plus various clues on the PFD....

It's not a mere mode change, its a flight control law change.

DH