I fly the development version of the FBW A320. Up until a few weeks ago prior to the T/D indication I would select a lower altitude. At the T/D indication I would push the altitude knob and start the descent. Now I am finding that at the T/D indication I push the altitude knob and nothing happens. I continue to fly at the current altitude. Also the flight plan changes and, for instance shows me at several thousand feet over my destination. Not being in anyway an expert flyer, has the procedure to descend in a managed position changed? If it has can you please advise me as to what to do. I have looked at the FBW manual on their web site but cannot find any reference to this. Thanks in anticipation.

Nothing has changed. I suspect operator error.

I have discovered that if I activate the APPR phase prior to the T/D indication the plane will respond to the managed descent mode. If this is the correct procedure then this is a very big change for me. Up until now I have not activated the APPR phase until passing through 15000 ft.

Just in case I did uninstall then re-install the aircraft.

This happened to me once when my FMC PROG page had a higher planned flflight level than the one I ended up using. The plane was thus still in climb mode and didn't start a descent until I changed the PROG FL. 

3 hours ago, Andy675 said:

Up until now I have not activated the APPR phase until passing through 15000 ft.

Approach mode is not activated before 15NM to destination. The Aircraft will do that on its own anyway. Only if you have a steep descent profile you might want to do it earlier.

Edited July 4, 20241 yr by Farlis

I checked it yesterday. All works fine in this regard.

Thanks for your replies. I accept that the problem is my end. As an experiment I installed the stable version and I have just had a perfect flight. There must be something I am doing wrong with the development version. I will keep on trying.

15 minutes ago, Andy675 said:

Thanks for your replies. I accept that the problem is my end. As an experiment I installed the stable version and I have just had a perfect flight. There must be something I am doing wrong with the development version. I will keep on trying.

Check out what @TuomasV wrote a few posts above. I guess that's the most reasonable cause for your behaviour.

I've experienced the same issue as Andy and I too reverted to the stable version where issue does not occur.  I haven't checked the PROG page as TuomasV suggested so will next chance I get.  

2 hours ago, totalstu said:

I've experienced the same issue as Andy and I too reverted to the stable version where issue does not occur.  I haven't checked the PROG page as TuomasV suggested so will next chance I get.  

I have checked the PROG page and all is in order. If I want to descend in managed mode I have to activate 'PERF - Approach' mode before starting my descent. What I am doing at the moment is 'pulling' the altitude knob, making a rapid descent then at about 15000ft activating APPR. pushing the altitude knob (I now get the star beside my selected altitude) and the plane then obeys any relevant restrictions. The pre-planned ILS Runway then also displays, the flight plan stops going mad (T/C randomly re-appears and strange altitudes display).

I don't like to say this, but I am so glad someone else also has this problem

 

A Thought: If my memory is correct this problem started after the update that included the 'missed approach' display

Edited July 5, 20241 yr by Andy675

What is your control scheme set to in MSFS settings? I have a vague recollection that it should be set to Legacy.

 

https://docs.flybywiresim.com/fbw-a32nx/settings/

5 minutes ago, BrammyH said:

What is your control scheme set to in MSFS settings? I have a vague recollection that it should be set to Legacy.

 

https://docs.flybywiresim.com/fbw-a32nx/settings/

Thanks for the reply, all the control settings are as they should be.

27 minutes ago, Andy675 said:

I have checked the PROG page and all is in order. If I want to descend in managed mode I have to activate 'PERF - Approach' mode before starting my descent. What I am doing at the moment is 'pulling' the altitude knob, making a rapid descent then at about 15000ft activating APPR. pushing the altitude knob (I now get the star beside my selected altitude) and the plane then obeys any relevant restrictions. The pre-planned ILS Runway then also displays, the flight plan stops going mad (T/C randomly re-appears and strange altitudes display).

I don't like to say this, but I am so glad someone else also has this problem

1) Are you 100% positive you are at the flight level which is entered in the PROG page? I suggest making a screenshot from the FCU, the PROG page and the PERF cruise/descent page. I'm 99% sure it's a flight phase problem (FMC thinking you are in another phase of flight).

2) No, you do NOT activate PERF Approach mode for descent. Don't do this. (It works probably because by pushing this you can basically "skip" right to the approach flight phase; this confirms the hypothesis that you are actually not in the correct flight phase when pushing for managed descent.

3) You do have a STAR entered in the FMC and no discontinuities?

 

6 minutes ago, Fiorentoni said:

1) Are you 100% positive you are at the flight level which is entered in the PROG page? I suggest making a screenshot from the FCU, the PROG page and the PERF cruise/descent page. I'm 99% sure it's a flight phase problem (FMC thinking you are in another phase of flight).

2) No, you do NOT activate PERF Approach mode for descent. Don't do this. (It works probably because by pushing this you can basically "skip" right to the approach flight phase; this confirms the hypothesis that you are actually not in the correct flight phase when pushing for managed descent.

3) You do have a STAR entered in the FMC and no discontinuities?

 

Thanks. Unfortunately I do not have the time to fly again now. However:

1) the planned altitude on the PROG page is the same as that displayed on the PFD gauge. Cruise is also displayed. The barometer is set at 'standard'

2) agreed

3) There are no discontinuities. I am not sure about the STAR (sorry but I am very much a layman!)

 

I did fly the stable version this morning and everything worked fine. I used this sequence: prior to T/D indication I selected a lower altitude, at T/D I pushed the altitude knob, a 'dot' appeared beside the selected altitude and the plane entered a managed descent. Is this procedure incorrect? If this is okay, it is exactly what I am trying to do with the development version, which worked prior to an update several weeks ago.

Thanks for your help.

19 minutes ago, Andy675 said:

I did fly the stable version this morning and everything worked fine. I used this sequence: prior to T/D indication I selected a lower altitude, at T/D I pushed the altitude knob, a 'dot' appeared beside the selected altitude and the plane entered a managed descent. Is this procedure incorrect?

No, that's the correct procedure. You might have been missing something which was not a problem on the (outdated) stable version, but is now (correctly so) on the dev version.