A320 interrupting the ILS
 

will appreciate if one of you, A320 experienced Drivers, will tell me what’s happening when during an ILS (LOG, G/S engaged, and Alt is set to go around altitude) the Alt knob is being pushed..? (in terms of modes changes) and how to revert back to ILS...

Nice one.

Above 400 ft RA :

DISENGAGEMENT CONDITIONS OF G/S ONLY

‐ The flight crew pulls out the V/S or FPA knob. LOC mode remains engaged, but G/S mode
disengages and V/S or FPA engages.
‐ The flight crew pushes or pulls the ALT knob. LOC mode remains engaged, and the mode
selected by the flight crew engages, as a function of the FCU selected altitude.

BUT :

The descent mode is a managed mode that may be engaged during cruise. It can be armed or
engaged in descent and approach phases (except if the FCU selected altitude is higher than the
present aircraft altitude).

Throughout the years I have had a few trainees caught out of startle effect pulling the ALT knob when setting the (higher) GA altitude ending up in a cancelled approach (no big drama, lesson learnt I guess). Regarding the "pushing" I am not sure, as the aircraft is on the correct vertical profile (vertical deviation centred) but the GA altitude is (let's say) above Your current altitude so technically nothing should happen but let's see if someone has experienced it and can shed some light. I will be in the SIM in a few days anyway so will try it out (still not close enough to retirement to try it on the line).

Correct. Descent mode cannot engage unless FCU altitude is below the present altitude. In case after GS capture the OPCLB mode gets engaged then push VS and follow capturing GS from above procedure by setting a suitable VS like -1800.

Have done both when it happened, went around or GS from above. It depends on many factors.

As far CLB mode getting engaged after pushing it will not.

Thanks, I believe we can almost 100% say that nothing will happen in relation to the OPs question.

...or press the 2 little red buttons. There's one close to each thumb ;)

How will that help? With FD in open climb? Good knowledge of automation is necessary. Sochi crash because he disconnected and then got disoriented.

He means each button in a different hand. :) and FDs = OFF.

I like Citation's solution too. If it is a quick reflex motion, such as the one for ALT* with excessive V/S, it would be elegant.

I'm with Check Airman on this one. :D Use the red buttons near both thumbs, F/D's off (Bird on if you want) and fly the ILS. Works like a charm, except for children of the magenta line.

There are approaches where FD or AP is mandated due to parallel approaches for example.

I'm sure even in this example, you'll be just fine hand flying raw data while the other person reconfigures everything.

After pressing the buttons, the FD mode doesn't matter.

While I have no doubt about your ability to fly raw data ILS, the correct procedure to use the two buttons on each side is to use them with two more buttons on the FCU i.e. the FDs and switch them off when you don't intend to use them. It's not smart to leave them in open climb mode while descending or vice versa. It can confuse the other guy. Knowing automation well does not indicate you cannot hand fly. In adverse environmental conditions disconnecting the AP at the drop of a hat can and has created problems.

I don't disagree at all Vilas. Just making the point that if the AT is off, there's no inherent danger in going against the FD. In this particular scenario, I'd obviously prefer the FD off.

i suspect this comes down to a difference in operational philosophy. Here, most people would rather just disconnect the AP than go through the interventions above, elegant as they may be.

Check, we do not disagree with your solution either.

Yet please observe: The task-sharing for CJ2's method:

either PF/PNF -> announce <explanative of choice>
PF -> move finger by 2 inches and push, turn then. Simultaneously call GEAR DOWN
PM - set L/G lever down
PF - read FMA "VS -2000"

Done in under two seconds, situation contained and the aircraft state / modes are exactly where they had been planned to be. No mental shift for the crew and all text-book callouts and cross-cockpit verifications.

Exactly ONE (admittable double) action of FCU, ONE command, and read of ONE commanded mode change. The full take-over and disconnect has more moves / tasks by order of magnitude.

Besides, personally, I'd go
- AP off and push to keep the nose from rising
- retard the TL's back to around 1/3 travel (a lot) but keeping ATHR on, even if limited
- call FD's off, then TL's to CLB again or ATHR off.
(8 "events" if I calculate correctly)


Feel invited to write yours, from where I am it looks like you are in CL detent with man thrust. :-) Google speed tape confusion, and it has killed more than few times already.


On the topic of "children of magenta", a term which is these days overwhelmingly used as a snotty remark to throw insults around by people who did not put the effort in to understand the message of that lecture ...
... waste of time.