ALPHA PROT/FLOOR/MAX
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Yes Amadis, I agree. But I don't know 1 french forum only for pilits like PPRuNe. English is not a problem for me. I understand 
I have posted on PPRuNe's french forum too.
Thanks a lot Dupre,
Ok, so in my ALT window, I have entered 2500ft. One time managed, one time selective!
I have posted on PPRuNe's french forum too.Thanks a lot Dupre,
Ok, so in my ALT window, I have entered 2500ft. One time managed, one time selective!
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Who cares?
Your questions bounce around like entries in an A-Z how to fly for beginners.... What started with an Original Post wrt Alpha Floor/Prot/Max very controversial in its understanding and being really well explained and expanded upon by other posters......
However, as is evident through other posts you make, questioning and seeking levels of clarification to diverse topics, you are angling to an agenda which may be through dare I suggest, what you have seen happen in your flight sim, game or whatever?
Any waypoint or level and speed constraint in the MCDU/FMGC is irrelevant to the topic you originally queried. If A/T is engaged it aims to maintain your speed with power....only if it no longer can for whatever reason will it lose the ability on thrust alone to maintain a selected or managed mode. Then Flight controls at that certain point, so well covered by Dupre and others, will lower the nose to maintain a speed commensurate and indicated by a combination of terms IE V and Alpha not necessarily the same values all the time.
Your last post talks about being in ALT selected or managed 2500Ft...... To me I read your alt is captured and maintained at 2500 FT it is only either selected or managed if you elect to change that with OP DES, DES, VS OR FPA .......ONLY THEN DOES IT BECOME SELECTED OR MANAGED.....I of course stand by to be corrected by the truly wise......(no sarcasm suggested there)
However, as is evident through other posts you make, questioning and seeking levels of clarification to diverse topics, you are angling to an agenda which may be through dare I suggest, what you have seen happen in your flight sim, game or whatever?
Any waypoint or level and speed constraint in the MCDU/FMGC is irrelevant to the topic you originally queried. If A/T is engaged it aims to maintain your speed with power....only if it no longer can for whatever reason will it lose the ability on thrust alone to maintain a selected or managed mode. Then Flight controls at that certain point, so well covered by Dupre and others, will lower the nose to maintain a speed commensurate and indicated by a combination of terms IE V and Alpha not necessarily the same values all the time.
Your last post talks about being in ALT selected or managed 2500Ft...... To me I read your alt is captured and maintained at 2500 FT it is only either selected or managed if you elect to change that with OP DES, DES, VS OR FPA .......ONLY THEN DOES IT BECOME SELECTED OR MANAGED.....I of course stand by to be corrected by the truly wise......(no sarcasm suggested there)
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Why North America
Still not really sure why this is in the North American Forum and not Tech.....
At the end of the Day it was the title that caught my attention, don't think I've really studied the North American or many othe region based forums before......maybe somewhat remiss on my part....
At the end of the Day it was the title that caught my attention, don't think I've really studied the North American or many othe region based forums before......maybe somewhat remiss on my part....
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To be honest the whole airbus logic is pretty hard to understand. For someone trying to get how it works with no formal airbus training, no experience in airbus aircraft and (at 14 years old) probably no experience in any aircraft at all, I can completely understand that the responses I and others post are somewhat difficult to digest.
Ok so here we go!
You have still not told me what altitude you are at, and whether you are in ALT mode or DES mode.
Notwithstanding.....
Say you have passed BANOX on the way to LORNI.
Say you are in the descent, passing 4000ft.
You have selected 2500 in the FCU alt window
There are 3 options for the descent... Managed, Open, Vertical Speed/FPA
Option 1. Managed descent (DES) -
Below the DES (green) on the FMA will be ALT magenta, and the altitude on pfd will be 3000 magenta. As the aircraft captures the altitude you will get ALT CSTR* then ALT CSTR and it will maintain 3000. When you get ALT CSTR, you will also get DES blue, indicating that after LORNI it is going to continue descent to 2500. On passing LORNI, DES will activate (become green), with ALT blue and 2500ft blue on the altitude tape.
Option 2. Open Descent (OP DES)
Below OP DES (Green) on the FMA will be ALT blue, and the altitude on the pfd will read 2500. The aircraft will ignore the constraint and descend straight to and maintain 2500
Option 3. Vertical Speed or FPA (V/S or FPA)
Same as for Open descent, it ignores the constraints and goes straight to 2500.
Ok so here we go!
You have still not told me what altitude you are at, and whether you are in ALT mode or DES mode.
Notwithstanding.....
Say you have passed BANOX on the way to LORNI.
Say you are in the descent, passing 4000ft.
You have selected 2500 in the FCU alt window
There are 3 options for the descent... Managed, Open, Vertical Speed/FPA
Option 1. Managed descent (DES) -
Below the DES (green) on the FMA will be ALT magenta, and the altitude on pfd will be 3000 magenta. As the aircraft captures the altitude you will get ALT CSTR* then ALT CSTR and it will maintain 3000. When you get ALT CSTR, you will also get DES blue, indicating that after LORNI it is going to continue descent to 2500. On passing LORNI, DES will activate (become green), with ALT blue and 2500ft blue on the altitude tape.
Option 2. Open Descent (OP DES)
Below OP DES (Green) on the FMA will be ALT blue, and the altitude on the pfd will read 2500. The aircraft will ignore the constraint and descend straight to and maintain 2500
Option 3. Vertical Speed or FPA (V/S or FPA)
Same as for Open descent, it ignores the constraints and goes straight to 2500.
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Yeah, thanks, I agree with all that but you had said that Ahr will manage F/S/O speeds...
So is there a special point in our F-PLN where we are at F/S or O speed? Does the FMGS really manage it or do we just fly these speeds???
Thanks a lot Dupre!
So is there a special point in our F-PLN where we are at F/S or O speed? Does the FMGS really manage it or do we just fly these speeds???
Thanks a lot Dupre!
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no worries.
The managed speed is taken from the FMGS phase
Takeoff phase has V2
Climb phase has climb speed.
Cruise phase has cruise speed (well, ok its mach, not speed)
Descent phase has descent speed
Approach phase uses O/S/F speeds
There are 2 ways to get into approach phase.
1) go to PERF page on mcdu, press "activate approach phase" then "confirm".
2) fly over a little "D" in a circle which appears on nav track, in nav mode, which from memory is 15nm from touchdown (Could well be wrong)... then it automatically activates approach phase.
The managed speed is taken from the FMGS phase
Takeoff phase has V2
Climb phase has climb speed.
Cruise phase has cruise speed (well, ok its mach, not speed)
Descent phase has descent speed
Approach phase uses O/S/F speeds
There are 2 ways to get into approach phase.
1) go to PERF page on mcdu, press "activate approach phase" then "confirm".
2) fly over a little "D" in a circle which appears on nav track, in nav mode, which from memory is 15nm from touchdown (Could well be wrong)... then it automatically activates approach phase.
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Ok, so the deceleration speed.
Thanks, but it was not exactly my question:
1) On the ND, we can see our waypoints with their names. On our F-PLN, is their also a moment where we can read F? S? O? We can read that D inside the circle, in our nav track but can we also read F/S or O?
2) When we fly over these speeds, what happens? Does it just fly this speed or does it consider it as a "waypoint" where we don't have to level-off but there is a speed constraint?
I hope my questions are clear....
Thanks
Thanks, but it was not exactly my question:
1) On the ND, we can see our waypoints with their names. On our F-PLN, is their also a moment where we can read F? S? O? We can read that D inside the circle, in our nav track but can we also read F/S or O?
2) When we fly over these speeds, what happens? Does it just fly this speed or does it consider it as a "waypoint" where we don't have to level-off but there is a speed constraint?
I hope my questions are clear....
Thanks
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O/S/F speeds do not appear on the FLT PLN, they do not appear on the ND.
The FMGS has no idea when you will select flaps. So it has no idea when you will be at what speed.
If you left it to fly the whole approach by itself, it would maintain green dot the whole way in.
Why? because you never selected any flaps, so it never went to S/F/Vapp.
I think what you are referring to are pseudo waypoints. There are 4 kinds. The display shows them as waypoints in parentheses
1. T/C (top of climb)
2. T/D (top of descent)
3. SPD LIM (speed limit)
4. DECEL (deceleration for approach)
None of these are for F/S speeds. Because the pilot has to command F/S speed by setting flaps. The aircraft cannot do that by itself.
clear?
The FMGS has no idea when you will select flaps. So it has no idea when you will be at what speed.
If you left it to fly the whole approach by itself, it would maintain green dot the whole way in.
Why? because you never selected any flaps, so it never went to S/F/Vapp.
I think what you are referring to are pseudo waypoints. There are 4 kinds. The display shows them as waypoints in parentheses
1. T/C (top of climb)
2. T/D (top of descent)
3. SPD LIM (speed limit)
4. DECEL (deceleration for approach)
None of these are for F/S speeds. Because the pilot has to command F/S speed by setting flaps. The aircraft cannot do that by itself.
clear?
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Thanks Dupre,
But you had said that the plane will MANAGE F/S/O speeds. Basically nothing will happen. The plane will simply respect it if there is a speed constraint = F/S/O. If not, it will just pass on that speed and target the next speed cstr. Right?
But you had said that the plane will MANAGE F/S/O speeds. Basically nothing will happen. The plane will simply respect it if there is a speed constraint = F/S/O. If not, it will just pass on that speed and target the next speed cstr. Right?
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ah yes I see your confusion.
F/S/O speeds are not constraints.
But they are the target speeds, while in the approach phase (the FMGS). To fly them, your speed must be managed (Push the speed knob) rather than selected (Pull the knob and rotate to desired speed).
F/S/O speeds are not constraints.
But they are the target speeds, while in the approach phase (the FMGS). To fly them, your speed must be managed (Push the speed knob) rather than selected (Pull the knob and rotate to desired speed).
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Thanks Dupre!
School has opened, so I won't be able to post between 8:30 and 17:00 (sometimes 16:00)---> Pa
I don't understand what you mean by target....
It will just pass over that speed, isn't it? Will it stop at that speed? Could you please explain?
Thanks!
School has opened, so I won't be able to post between 8:30 and 17:00 (sometimes 16:00)---> Pa
I don't understand what you mean by target....
It will just pass over that speed, isn't it? Will it stop at that speed? Could you please explain?
Thanks!
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target speed = speed it will maintain for you.
It works just the same as if you select the speed.
Maintains the speed with pitch or thrust depending on your mode.
As discussed earlier, maintains with thrust when in a vertical path mode V/S, FPA, DES or ALT. Maintains speed with pitch in a thrust mode CLB, OP CLB, OP DES
It works just the same as if you select the speed.
Maintains the speed with pitch or thrust depending on your mode.
As discussed earlier, maintains with thrust when in a vertical path mode V/S, FPA, DES or ALT. Maintains speed with pitch in a thrust mode CLB, OP CLB, OP DES
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Thanks Dupre,
If It maintains that speed, what if there is a waypoint after it with speed restriction? Till when does it manage it? Till we pass it?
If It maintains that speed, what if there is a waypoint after it with speed restriction? Till when does it manage it? Till we pass it?
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Hm good question.
I believe that it will not go below O/S/F speed to meet a restriction.
And if the restriction is a faster speed than O/S/F, then the restriction is met anyway.
So setting a restriction while in approach phase will have no effect. I think.
I believe that it will not go below O/S/F speed to meet a restriction.
And if the restriction is a faster speed than O/S/F, then the restriction is met anyway.
So setting a restriction while in approach phase will have no effect. I think.
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Thanks Dupre,
I think that these speeds are just some kind of reference for the pilots. It does not do anything.
Check this video:
https://www.youtube.com/watch?v=bjGT9aJU6jo
At 10:30, you can see that selected speed = S speed
But I think the plane can go below S speed if the selected speed is (below it).
What do you think?
You had said for alpha floor:
"Note 2.αfloor is activated through the A/THR system, when:‐α is greater than αfloor (9.5 ° in configuration 0; 15 ° in configuration 1, 2; 14 ° in configuration 3; 13 ° in configuration FULL) or‐Sidestick deflection is greater than 14 ° nose up, with either the pitch attitude or the angle-of-attack protection active."
So you were talking about the flaps, isn't it? So for e.g, Alpha floor will activate if AoA = 9,5° if our flaps are retracted?
Thanks
I think that these speeds are just some kind of reference for the pilots. It does not do anything.
Check this video:
https://www.youtube.com/watch?v=bjGT9aJU6jo
At 10:30, you can see that selected speed = S speed
But I think the plane can go below S speed if the selected speed is (below it).
What do you think?
You had said for alpha floor:
"Note 2.αfloor is activated through the A/THR system, when:‐α is greater than αfloor (9.5 ° in configuration 0; 15 ° in configuration 1, 2; 14 ° in configuration 3; 13 ° in configuration FULL) or‐Sidestick deflection is greater than 14 ° nose up, with either the pitch attitude or the angle-of-attack protection active."
So you were talking about the flaps, isn't it? So for e.g, Alpha floor will activate if AoA = 9,5° if our flaps are retracted?
Thanks
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1. Yes, you can select a speed all the way down to Vls if you desire, at any stage of flight including approach.
In this video they fly the whole approach in selected speed, and only managed speed from 14:46. If they had been in managed speed from the start, the aircraft would have maintained O/S/F speed as they had flaps 0, 1, 2/3.
Not sure why they did this - it looks like maybe they were given minimum 170kt until 4 or 5 miles by ATC?
2. Yes. Configuration means Flap/Slat setting.
In this video they fly the whole approach in selected speed, and only managed speed from 14:46. If they had been in managed speed from the start, the aircraft would have maintained O/S/F speed as they had flaps 0, 1, 2/3.
Not sure why they did this - it looks like maybe they were given minimum 170kt until 4 or 5 miles by ATC?
2. Yes. Configuration means Flap/Slat setting.
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Hi,
Thanks, do you confirm that if AoA = 9,5° and flaps retracted, Alpha floor comes?
If AoA = 15° and flaps conf 1/2, alpha floor comes?
If AoA = 14° and flaps conf 3, alpha floor comes?
If AoA = 13° and flaps full, alpha floor comes?
2) Ok, so for Take-Off, the ambrr = is not there. Basically, Vmax is there but that's all. Right?
Thanks!
Thanks, do you confirm that if AoA = 9,5° and flaps retracted, Alpha floor comes?
If AoA = 15° and flaps conf 1/2, alpha floor comes?
If AoA = 14° and flaps conf 3, alpha floor comes?
If AoA = 13° and flaps full, alpha floor comes?
2) Ok, so for Take-Off, the ambrr = is not there. Basically, Vmax is there but that's all. Right?
Thanks!
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Yes, you are right.
Thanks a lot Dupre for your precious help!
Let's finish this great thread with the last questions.
Well, I am sure that I am wrong because you can't give the AoA. Just wanted some small explanation on Dupre's F-COM quote.
Thanks,
AF330
Thanks a lot Dupre for your precious help!
Let's finish this great thread with the last questions.
Well, I am sure that I am wrong because you can't give the AoA. Just wanted some small explanation on Dupre's F-COM quote.
Thanks,
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haha my pleasure. The thread has forced me into sections of the fcom that I haven't been into in a long time and I have learned some things along the way. Also I have learned something about providing clear and concise answers!
With my first reply I had no idea the monster thread this would become! Certainly did not know there were that many people watching it's progression.
To answer your last questions... you are right about a.floor and AoA. But there is no indication of AoA in the cockpit so you cannot be sure where it will occur.
On takeoff, you have amber= just like in any phase of flight, below 20,000ft and not in conf Full.
With my first reply I had no idea the monster thread this would become! Certainly did not know there were that many people watching it's progression.
To answer your last questions... you are right about a.floor and AoA. But there is no indication of AoA in the cockpit so you cannot be sure where it will occur.
On takeoff, you have amber= just like in any phase of flight, below 20,000ft and not in conf Full.
