Alpha/Speed Lock protection

[Illuminati270]

Aircraft Version

Development

Build info

{
  "built": "2021-06-12T03:56:37+00:00",
  "ref": "master",
  "sha": "476e1ed0d7fa91d0d152a2da762331d25b6067f4",
  "actor": "tracernz",
  "event_name": "manual"
}

Describe the bug

Alpha Lock protection doesn't allow the slats to be retracted when the aircraft is flying high AoAs.

Expected behavior

Whenever the flap lever is set to 0 with AoA >8.5° and the speed is less than 148kts, the Alpha Lock will avoid slats retraction.

Steps to reproduce

1. Takeoff with flaps 2 or 3
2. Keep yourself below 148kts, fly a higher than 8° AoA
3. Set flap lever to 0
4. No Alpha Lock activation on ECAM DU 1
5. Slats retracting normally

References (optional)

DSC-27-30-10

Additional info (optional)

No response

Discord Username (optional)

Illuminati

[aguther]

Some comments to keep in mind when this will be implemented:

• AoA values might not be used 1:1 due to limitations the flight model of MSFS (it needs to be checked how value of 8.5° compares to alpha protection, floor and max; we don't have the real world values of those so that not that easy)
• your reference speaks about slats only, so I assume this really applies only to slats which cannot be controlled individually
• if it's about not being able to get into CONF 0 but for sure in CONF 1 from higher configurations then this would be possible, but to me it sounds like slats would not retract at all but flaps do

[Illuminati270]

I fully understand about the AoA. I did the test with 9° AoA to make sure it wasn't Alpha Locking.

You mentioned that slats can't be controlled individually, but the auto-retraction (>210kts) retracts Flaps from CONF 1+F to CONF 1, actually working perfectly! What if the same code is used with a different rule?

AoA >8.5° Speed <148kts

• Retract only flaps. (Like when 210kts is reached at CONF 1+F)

And yes, that's how the system works. The slats won't retract (If you have a look on QRH, you'll see that Slats have much more performance impact than the flaps itself).

[aguther]

Look, the CONF 1+F to CONF 1 is indeed something we can inhibit and that will comply with what you’ve described by accident because CONF 1+F has slats 18° and flaps 10° while CONF 1 has only the flaps changed to 0°.

Now let’s talk about CONF 2: slats = 22° and flaps = 15°

So taking it strict it would mean flaps go to 0° but slats stay at 22°. And that’s something we cannot do right now.

That’s all I wanted to document.

[Illuminati270]

Got your point.

I mean, the system could be partially implemented only for CONF 1+F, as that would already inhibit someone to select Flaps 0 while flying way below S-speed (on very low weights, of course). Yet, the CONF2/3 -> CONF 0 wouldn't be covered if someone selected by accident (which is mainly why this protection was designed) CONF 0 instead of correct order which would be:

CONF2/CONF3 -> CONF1+F -> CONF 0

Is it a FS2020 restriction right now? Flap/slat jammed is a endless world of possibilities on the Airbus!

[aguther]

Yeah that is something we could do as a first step, only inhibit CONF 1 or CONF 1+F to CONF 0 in those conditions.

it would be: 1+F -> 1 1 -> 1

Yes, it’s limitation of MSFS. there is only one lever for slats/flaps…

[donstim]

Is it worth trying to pick this up again in terms of only inhibiting the CONF 1 or 1+F to 0 slat retraction? Or has it already been done?

[Illuminati270]

Is it worth trying to pick this up again in terms of only inhibiting the CONF 1 or 1+F to 0 slat retraction? Or has it already been done?

To this date, it seems not yet implemented. But I believe that's because what Aguther explained on the thread above.