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AF330

FMA A320 modes

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Hi!

 

I wanted to learn the different modes we can read on the FMA for HDG and ALT with the colours.....etc. I read F-COM Autoflight and wanted to confirm what I had understood and ask some questions!

 

ALT.

 

On the FMA, when you can read ALT, are you flying the plane manually? Because you have 4 modes for altitude:

 

- CLB (managed)

- OP CLB (Selective)

- V/S (vertical speed)

-ALT!

 

Thanks!

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The only part of the FMA that indicates you are hand flying is in the upper right. If there is no AP1 or AP2 or AP1+2 annunciated you are handflying.

 

All the other annunciations in the FMA indicate what flight guidance modes are provided with the flight director.

 

If you handfly with the flight directors off, nothing will be annunciated in the FMA.

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I don't know Airbuses but in many other AP/FD systems ALT simply means you are in altitude hold mode. I have ALT in my Cirrus/G1000 that I fly and this is what it means.

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Euh....wait! Getting confused....

 

1) Altitude capture = Altitude captureD?

So when you are in an OP CLB, CLM, V/S...etc, it will arm ALT? And when you reach your next altitude (on the FMGC or the FCU), it will show ALT?

 

2) If it is altitude captured, in managed mode, is it only for waypoints where we have to level-off?

 

Thanks

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Hey.... read F-COM 1.22.30 P71 SEQ 110 REV 35 - Autoflight A320.

 

For altitude on FMA, it says:

 

ALT* : ALT* green, in case of FCU selected altitude capture.

ALT CST* : ALT CST* green, in case of ALT CSTR capture (vertical profile)

ALT is green, when the FCU selected altitude is held.

ALT CST: ALT CST is green, when an ALT CST is held (vertical profile)

 

1) Ok..... So when we are in managed mode, and our ALT CST is approaching, it will show ALT CST* in green, right?

 

2) When we enter an altitude in the FCU, and if we haven't captured it yet, it will show on the FMA ALT* in green, right?

 

3) When our managed altitude is held, it will show ALT CST in green, right?

 

4) When our FCU altitude is held, it will show ALT, right?

 

5) Sometimes, we just have to pass a waypoint over X altitude. Is that considered as ALT CST? Because we don't have to level-off....if yes, when we will pass over that waypoint over X altitude, will it still show ALT CST (it can only happen in managed mode)?

 

Thanks a lot!

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Well....what is the difference between held and captured?  :unsure:

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"Held" is "exactly at" an altitude/FL and keeping it.

 

"Captured" is "still acquiring" an altitude/FL - you are close, but haven't reached it yet exactly. Still slowly climbing or descending.

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Thanks a lot....

 

So what is "armed"? If ALT (CST) * means that you are going to held the altitude (capture). But when ALT (CST) is in displayed in blue, it's armed! So what is the difference between arm and capture?

 

Thanks

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Whenever you set an altitude in the FCU, you are telling the FMGC that you want a different altitude than the one the aircraft is currently at.

You then pull or push, depending on what you want to do.

 

If you pull, you will either get an OP CLB or OP DES.  In an OP CLB or OP DES, the aircraft will ignore any altitude contraints set in the FMS.  So it will only show ALT in cyan underneath OP CLB or OP DES.

 

If you push, the aircraft will attempt to honor any and all altitude constraints set in the FMS.  You will get CLB or DES then underneath CLB or DES, it will either show ALT in cyan or ALT CST in magenta.   There may be an altitude constraint set in the FMS.  If the FMGC calculates the aircraft will meet the altitude constraint without having to stop at the altitude constraint, it will just show ALT in cyan.   If the FMGC determines the aircraft needs to level off at the altitude constraint, it will show ALT CST in magenta and then indicate what altitude it is constrained to on the altitude tape of the PFD in magenta.

 

Once the aircraft gets to the point of altitude capture, the ALT/ALT CST transitions from the second line to the top line of the FMA to show either ALT* or ALT CST* to indicate it is in the process of capturing the altitude that is either set in the FCU or the altitude constrained by the FMS.     Once the altitude is captured the FMA will display one of the following ALT, ALT CRZ, or ALT CST, depending on the situtation.

 

If it is ALT CST, the aircraft will only level as long as it is constrained, after it passes the constrained waypoint, it will resume the climb or descent to the altitude set in the FCU.  At which point it will then show either CLB or DES, with ALT in cyan underneath, and the FCU preselected altitude in cyan on the altitude tape of the PFD.

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So what is the difference between arm and capture?

James Bond was ready and armed ...

 

.. so he could attempt to capture Blofeld.

 

Do you now see the difference between 'arm' and 'capture'?  :wub:

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Thanks a lot....

 

Is their a code for colours?

 

Blue = ?

Green = ?

Magenta = ?

White =?

 

Thanks....

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Ok so if we are not in managed mode (selective mode: OP CLB...) it will show first arm ALT in blue on the second line and OP CLB on the first line. When we we will reach the altitude on the FCU, it will show ALT* in green on the first line.

 

But when we are in managed mode, ALT will arm only if we have to pass over/under a waypoint in blue on the second line. If the next waypoint is an ALT CST, it will arm ALT CST in magenta (second line). On the first line, we can read CLB or DES. When we have to level-off on one of our waypoints, it will show ALT CST* on the first line in green.

 

1) Everything right?

2) So ALT basically means that we are flying without any level-off, right?

3) So we can never read ALT on the first line?

 

4) So blue = armed

- Green = when we are at level. Right?

 

5) In managed mode, if we don't have to level off, it will show ALT in blue on the second line? If yes, it would mean that we can read that we can only read ALT CST* on the first line.....

 

Thanks

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A couple of "colour assignments" for the FMA, roughly speaking - you have all the detailed resources at your fingertips already:

 

blue = armed (selected)

magenta = armed (managed)

green = active

white = automation status (A/THR, A/P, F/D)

 

As an example: Imagine you are in a managed descent with altitude constraints:

 

If you dial in an altitude (in your ALT window on the FCU) higher than the constraint: ALT arms in blue (a pilot-selected ALT limits your descent)

If FCU ALT is lower than your constraint: ALT arms in magenta (a STAR-related ALT limits your descent, so kind of "managed")

 

CSTR never gets armed; it's ALT that will be armed. CSTR is for active modes only. The CSTR information is covered by the colour magenta of the armed ALT.

 

ALT is shown in green when ALT capture (ALT* = ALT star) has completed. If the altitude kept is your cruise altitude, the FMA shows ALT CRZ in green.

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Wood: "If you will either get an OP CLB or OP DES. In an OP CLB or OP DES, the aircraft will ignore any altitude contraints set in the FMS. So it will only show ALT in cyan underneath OP CLB or OP DES. If you push, the aircraft will attempt to honor any and all altitude constraints set in the FMS. You will get CLB or DES then underneath CLB or DES, it will either show ALT in cyan or ALT CST in magenta. There may be an altitude constraint set in the FMS. If the FMGC calculates the aircraft will meet the altitude constraint without having to stop at the altitude constraint, it will just show ALT in cyan. If the FMGC determines the aircraft needs to level off at the altitude constraint, it will show ALT CST in magenta and then indicate what altitude it is constrained to on the altitude tape of the PFD in magenta."

 

Thanks olli! ;)

 

1) But he/she says that if you are in managed mode and if your next waypoint is an ALT CST, it will show ALT CST in magenta on the second line. (So it has captured it, basically armed it!) Do you agree?

 

2) You say: " If you dial in an altitude (in your ALT window on the FCU) higher than the constraint.... [...]"

 

How can you have constraints if you enter an ALT on the FCU? It would mean that you are in managed mode. But which constraint are you talking about? If you enter an ALT in managed mode, it will respect every constraint till that altitude (entered on the FCU) and level off there (entered in the FCU). Wood said that if your next waypoint is a CST, in managed mode, it will show ALT CST in magenta and ALT if it is not a CST (so you don't have to level-off). So which constraint are you talking about?

 

3) You said that blue = armed and selective mode

 

But you can read ALT in blue if you are in managed mode, AND if your next waypoint is not a CST (you don't have to level-off)

 

Thanks

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1)

Different software version?

 

2)

Constraints related to the following waypoints. My example was a STAR (STandard Arrival Route) which very often contain CSTRs.

 

3)

I think I mentioned that in my example. Mind that a managed descent is carried out no further than to the higher one of two altitudes: a) altitude in the FCU ALT window (this is a pilot-selected figure), b ) altitude in an ALT CSTR (this is coded into the navdata, so part of the managed side of things)

Bottom line is:

A managed descent right down to the FCU ALT is a descent down to a selected (= pilot-selected) altitude ... so shows in blue, despite the fact that the descent is still managed.

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http://www.youtube.com/watch?v=bjGT9aJU6jo

 

It's a very nice video! 

 

So when it is an OP CLB, here are the steps:

 

1) It shows on the first line OP CLB in green.

2) It arms ALT (in blue) on the second line.

3) It captures the selected altitude and shows ALT* in green (which means that it has been captured) on the first line.

4) ALT is green, the altitude has been held.

 

 

So when it is a managed climb and if our next waypoint is an ALT CST, here are the steps:

 

1) It shows on the first line CLB in green.

2) It arms ALT CST in magenta on the second line.

3) It captures the selected altitude and shows ALT CST (which means that it has been captured) in green on the first line.

4) ALT CST is green, the altitude constraint has been held.

 

I am not sure of this one, Wood and Olli are saying 2 different things!  ^_^ 

 

 

So when it is a managed climb and if our next waypoint is not an ALT CST, here are the steps:

 

1) It shows on the first line CLB in green.

2) It arms ALT in blue on the second line.

3) It passes over/under the waypoint at X altitude and shows ALT* (which means that it has respected the CST) in blue on the second line.

4) We can still read CLB in green on the first line.

 

So when we enter a V/S, here are the steps:

 

 

1) It shows on the first line V/S in green.

2) It arms ALT (in blue) on the second line.

3) It captures the selected altitude and shows ALT*  in green (which means that it has been captured) on the first line.

4) ALT is green, the altitude has been held.

 

Everything right?  :rolleyes:

 

Take care,

AF330

 

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