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How do I disable alpha floor in the A320 to land?

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Everytime I try to manually land, the Airbus engages auto throttle and wants to go around.

How do I stop that from happening?

 


FSX | DCS | X-Plane 11 | MSFS 2020 | IL2:BoX

Favorite aircraft currently: MSFS Savage Cub

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I don't believe there is a way to remove that protection; however, you should not be hitting it at normal landing speeds. Are you using the Vspeeds from the FMC when you land?

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Honestly, I'm just hand flying it and not paying too much attention to numbers right now.

Just keeping the speeds above the low speed indicator on the speed tape. The moment I idle down and float over the runway and before I've touched down, the A/T will engage and force me to go around.

Edited by Slides

FSX | DCS | X-Plane 11 | MSFS 2020 | IL2:BoX

Favorite aircraft currently: MSFS Savage Cub

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If you look on the left side of PFD, you will see an amber section on the airspeed indicator strip, if your airspeed strays into that zone, that will trigger Alpha Protection.

If your airspeed drops into that zone, the aeroplane's systems will limit your pitch and roll authority and it will run the throttles up, and this is so that you don't stall and spin in. So you don't want to turn it off, because if you do, you will die. What you need to do is keep the speed indicator out of that amber zone. Note that you have to keep it out of there for a couple of seconds before Alpha Protection disables, so don't let it drop back in there there, or you'll be back to square one.

Edited by Chock
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Alan Bradbury

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1 hour ago, Rusty10 said:

Hi

Retard throttles at or below 30ft?

It just likes to float until it stalls. I'll need to slam it in the deck


FSX | DCS | X-Plane 11 | MSFS 2020 | IL2:BoX

Favorite aircraft currently: MSFS Savage Cub

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Just curious if you are trying to land with almost zero fpm descent rate? Perhaps stay nearer to 100 fpm. According to the interwebz a hard landing is on average 240 fpm or more...

https://aviation.stackexchange.com/questions/47422/what-is-the-typical-touchdown-vertical-speed-of-a-large-airliner


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24 minutes ago, HighBypass said:

Just curious if you are trying to land with almost zero fpm descent rate? Perhaps stay nearer to 100 fpm. According to the interwebz a hard landing is on average 240 fpm or more...

https://aviation.stackexchange.com/questions/47422/what-is-the-typical-touchdown-vertical-speed-of-a-large-airliner

Looks like I'm another victim of trying to make every landing a greaser like most simmers.

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FSX | DCS | X-Plane 11 | MSFS 2020 | IL2:BoX

Favorite aircraft currently: MSFS Savage Cub

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A real world A320 pilot has completed several you tube videos on various aspects of flying the A320NEO. Check them out they are very well done!

https://www.youtube.com/user/filanjix/videos

John

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IRL (I don't know about the MFS one) there is no way should be activating the alpha floor protection during a normal landing, you shouldn't be in the orange bit of the speed tape, the top of that represents Vref. An A320 is not a Cessna, you don't stall it on to the runway!

IRL you can override the Alpha Floor protection by disengaging the A/THR with the buttons on the thrust levers, then just nudge the thrust levers to where you want thrust to be at, this will permit you to go to Alpha Max but the FBW will keep the pitch outside of the AoA stall range and you'll have to hold the stick back (in plain English this means it will limit how much nose up pitch you can apply to avoid stalling, keeping you out of the red zone of the speed tape)

There is an excellent demo of this at 9m18s below, you will see the Alpha Floor overrided 9m55s

 

Edited by ckyliu

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Alpha floor should be inhibited at a certain height. Something like 100ra?

Anyway, are you closing the thrust levers to land? It’s not like the Boeing where they automatically close. 

Note: not flown either of the big jets in MSFS  so don’t know what is accurate. 

Edited by 2reds2whites

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10 minutes ago, 2reds2whites said:

Alpha floor should be inhibited at a certain height. Something like 100ra?

Anyway, are you closing the thrust levers to land? It’s not like the Boeing where they automatically close. 

Note: not flown either of the big jets in MSFS  so don’t know what is accurate. 

I feel like the sim gives too little of a window between float and stall on the A320.

If I idle too early, it will start to stall and alpha floor will kick in.

If I idle late, it won't stop flying before I run out of runway.

I've only tried a few landings so will need to practice more.

One unrelated thing I'm realising is that as good as DCS is, I don't think it does a convincing enough job of modeling float/ ground effect.

Edited by Slides

FSX | DCS | X-Plane 11 | MSFS 2020 | IL2:BoX

Favorite aircraft currently: MSFS Savage Cub

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Ground effect float on a small-winged F-18 is going to be a lot different from float on a tubeliner with a wingspan that you could park 2 F-18's on.

Ground effect happens at roughly half the wingspan distance above the ground. That means the F-18 isn't even going to see ground effect until you're 18 feet above the runway, and if you're landing it properly you won't even notice it as much because you're essentially supposed to "controlled-crash" it into the deck with no flare. A typical carrier landing (and by extension runway landing because pilots practice for carrier landings whenever they can) is 700-800fpm descent rate, which would infuriate your Airbus passengers. At that descent rate it takes about a second and a half to go from the beginning of ground effect to touchdown. By the time you even notice the ground effect you're already down.

Meanwhile the Airbus is getting ground effect more than twice as high, and you're flaring which gives you extra lift (especially if you're fast), so it's a good deal more noticeable, and you're shooting for a much lower descent rate so that you don't break the airplane (or the passengers), so you're gonna mess around in ground effect for a much longer period of time and therefore notice it more.

I haven't done a thorough check to see if the calculated V speeds are accurate in the default jetliners, but I will say that I messed with that A320 landing challenge for a good while the other day and never had an issue with hitting alpha floor. If you're on glideslope and fairly close to the correct approach speed, you should be able to reduce thrust to idle over the threshold and land without issue.

If you would like to drink from a fire hose of information on proper Airbus landing procedure, check this page out:

https://safetyfirst.airbus.com/control-your-speed-during-descent-approach-and-landing/

 

 

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If MSFS2020 works like the real jet, there is an easy way to manage speeds.

Assuming the thrust lever is in the notch and SPEED is the mode shown in the Flight Mode Annunciator above your Primary Flight Display.

Most often you will want to push the speed selector knob which will blank the speed window and the jet will fly "managed speed" on autothrust. Think of pushing the speed knob to give control to the jet and pulling the speed knob to take control yourself. Managed speed will refer to the calculated speeds on the FMC and also respect gear and flap limit speeds. 

So lets say you are flying a vanilla simple RNAV or ILS approach. Your thrust lever is in the "notch" and  As you approach your final approach fix you will be slowing and configuring for landing; 160 to 180 knots and flap lever 2 works great. As you intercept your glideslope to the runway, press the speed knob for "managed speed" put the gear down, configure flap lever to match your approach page in the FMC. The jet will slow and the autothrust will maintain your VLS (landing speed in this case) plus a factor for winds and gusts automatically. At about 20 feet the airplane will tell you to "Retard" at about 20 feet. Slowly pull the trust levers to idle and land the jet.   

At 50 feet the jet pitches 2 degrees to simulate the feel of entering ground effect (about half the wingspan of an aircraft, but in a fly by wire jet they do this little trick to induce a little "feel" for the runway). The Airbus already has about 4 degrees nose up at that point, so just another two degrees or so and she bleeds energy and settles right in. Make you look like a hero much more often than you do on the B737-800 & 900.

The hackneyed (but still funny) joke is that the first "Retard" is a verb. The second "retard" is a noun. 

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