FBW A320 Latest Mod question

[Zimmerbz 168]

I have 2 days worth of the latest mod and have had the same thing happen twice and I am wondering if anyone else has this.  I am on final into KALB and KORD with AP off, FD off and A/T on.  I was in selected speed at 180 kts until about 5-7 nm out then switch back to managed.  I drop the gear, and reduce my flaps accordingly until they are full.  Both times, my speed dropped well below what was calculated in PERF and I started to get "stall, stall" warnings.  To avoid going into alpha floor, I turned off the A/T and went manual in order to keep my speed up and land.  The entire time i was getting "don't sink, don't sink" until I landed.  Could this be a custom AP issue by FBW?  I have been deep into the Airbus on both sims for years and haven't done anything out of the ordinary on these two flights.  Thought i would see if anyone else has this.

[Adamski_NZ 952]

Something not quite right here ...

I use the latest DEV version and don't have this problem. Have you entered all the info in the APP page of the MCDU?

On my approaches, I let the A320 do *everything* in "Managed" mode - right down to the decision height ... dropping flaps and gear when necessary, but leaving the throttle and speed knob well alone.

The only time(s) I do anything on the main panel is to set and activate new altitudes (select new altitude then click the knob up for "Managed").

I engage LOC when lined up laterally, then APP when the G/S diamond lines up. Once I'm at decision height (typically 300ft) I disengage the A/P (as the FBW doesn't have autoland yet) and fly the remainder in manual - but leaving A/T as it was (engaged). If you've set up the autobrakes correctly, they should deploy when you go into reverse thrust.

I'm not a real A320 pilot, so I've no idea whether all this is entirely accurate for RL, but it seems to work fine for me in the sim!

 

Edited January 22, 2021 by Adamski_NZ

[Zimmerbz 168]

2 minutes ago, Adamski_NZ said:

Something not quite right here ...

I use the latest DEV version and don't have this problem. Have you entered all the info in the APP page of the MCDU?

On my approaches, I let the A320 do *everything* in "Managed" mode - right down to the decision height ... dropping flaps and gear when necessary, but leaving the throttle and speed knob well alone.

The only time(s) Ido anything on the main panel is to set and activate new altitudes (select new altitude then click the knob up for "Managed").

I engage LOC when lined up laterally, then APP when the G/S diamond lines up. Once I'm at decision height (typically 300ft) I disengage the A/P (as the FBW doesn't have autoland yet) and fly the remainder in manual - but leaving A/T as it was (engaged). If you've set up the autobrakes correctly, they should deploy when you go into reverse thrust.

I'm not a real A320 pilot, so I've no idea whether all this is entirely accurate for RL, but it seems to work fine for me in the sim!

 

Yes.  I am doing everything by the books. 

[CaptBillyBob 51]

Did you activate the approach phase?

[Zimmerbz 168]

24 minutes ago, CaptBillyBob said:

Did you activate the approach phase?

Yes. I typically do that around 8000ft since I am in selected speed to keep under 250kts.  But even if I didn't activate approach phase, it would automatically activate crossing the decel point in the route.

[Andreas Stangenes 1,628]

Are you quite sure that your throttle was in the CL detent? Perhaps, if your real life throttle is a bit squirrly, it might make the throttle go out of CL intermittently and that may cause your speed to drop. 

[Tom Wright 438]

I had this happen to me as well. Using the latest stable build. The speed just bled off straight through the VLS speed and almost into a stall.

Luckily I noticed what was happening in time and quickly put it back in selected speed with the VAPP speed dialed in manually.

[Adamski_NZ 952]

7 hours ago, Tom Wright said:

I had this happen to me as well. Using the latest stable build.

Aah ... I see. I always use the DEV version. Zimmerbz just said "the latest mod" so I presumed he meant the DEV one.

[Zimmerbz 168]

7 hours ago, Adamski_NZ said:

Aah ... I see. I always use the DEV version. Zimmerbz just said "the latest mod" so I presumed he meant the DEV one.

Sorry, latest Dev mod

[Zimmerbz 168]

On a flight today info KSDF same thing happened.  It has to be some sort of bug.  This time, i was in selected speed (180kts) flaps 2 until 5nm from 17R.  At 5NM, i dropped the gear and went into managed mode.  I selected flaps 3 at about 160kts, then full shortly after.  My speed dropped all the way to about 120 kts.  This time, however, i did not get "don't sink, don't sink" and managed to land without issue.  I was in CLB detent and made sure the approach was activated.  This has to be some sort of bug

[Donstim 109]

Next time this happens, check the PERF APPR page and confirm what Vapp should be. Then confirm that the magenta bug on the speed tape is set to the same value when in full landing flap configuration. Screen shots or a video that would enable the developers to reproduce it would be great. Here is where you can report it if so inclined:  https://github.com/flybywiresim/a32nx/issues

[mattn 45]

I discovered last week that I wasn't setting up the weights, fuel, and vspeeds properly compared to the OFP that simbrief gave me. 

Check out this YT vid, it explains it nicely:

Apologies if you know all of this or are a real bus driver etc. 🙂

Edited January 24, 2021 by mattn
added words.