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# Airbus FMS

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# Airbus FMS

6th Mar 2010, 02:53

Join Date: Dec 2007
Location: Changi
Posts: 122
Airbus FMS

Hi Guys,

Just want to check, how do we program an in-between restriction for a waypoint ? Like you need to cross a certain waypoint above 4000ft and below 6000ft? A good example is a EGLL SID.

Do we have to :-

1) Monitor the at or above 4000ft restriction manually by eyeballing the performance?

OR

2) The FMS is smart enough to just display the most limiting? Thus we can assume that the A/C will meet the at or above 4000ft? On my FMS, the height restiction is displayed ONLY as at or below 6000ft.

Thanks a lot for your help. Really new to the Airbus game.

Cheers,
lion-g
6th Mar 2010, 08:08

Join Date: Mar 1999
Location: UK
Posts: 362
Assuming you're on a SID, are you cleared above 6000', or is that your stop altitude. If so just put above 4000' at the selected point. The difficulty is if you're cleared to say 9000', but can't climb above 6000' till past this waypoint.
Putting a pbd (place bearing distance) just after this waypoint, and constraining this to below 6000' would be a less than ideal fudge. Is there a more elegant way?
6th Mar 2010, 08:18

Join Date: Feb 2010
Location: uk
Posts: 58
what is an FMS?

it' s a FMCG.

then you can enter altitude condition by pressing + or - 5000ft.
you can create points by entering in this format : name of station/radial/distance then ad the altitude you want to overfly at pseudopoint.
6th Mar 2010, 08:41

Join Date: Dec 2007
Location: Changi
Posts: 122

The problem is - we can only set 1 constraint in the ALT constraint selection. If say at waypoint X(in FMS), we need to be between 4000ft and 6000ft. How can we go about setting it ?

In my previous fleet, we can go 4000A6000B (4000 above and 6000 below) but in airbus we can only set one as far as I can remember.

Thanks
6th Mar 2010, 08:45

Join Date: Oct 2009
Location: UK
Posts: 1,271
it' s a FMCG.
Or is it a FMGC?

Lion-g - I miss the friendly Boeing FMS ability of being able to put two constraints at a way point also. Airbus only permit one - so choose the most limiting and ensure the other is made with intelligent speed selection.
6th Mar 2010, 08:51

Join Date: Mar 2000
Location: Sunrise Senior Living
Posts: 1,297
Simple - you can't enter 'window constraints' in the A320 family FMGC. The database people can, but us mere mortals can't.

Cheers
mcdhu
6th Mar 2010, 13:14

Join Date: Jul 2008
Location: south pacific vagrant
Posts: 1,309
Alternatively, create another waypoint 1NM on one side of it and give it the other constraint
6th Mar 2010, 14:06

Join Date: Jul 2006
Location: 'tween posts
Posts: 195
quick fix

here is what I do ,
If the constrain is 'tween say 4000 and 6000 I would put in the constrain as 5000!
6th Mar 2010, 15:29
The Bumblebee

Join Date: Jul 1999
Location: Inside the shiny tube.
Posts: 329
I'd put -6000, if you put +4000 and it cannot be met, ithe FMGC will show it in amber. However, if you are climbing too fast, it will stop climbing at 6000. Now you just have to monitor to see if you are crossing the waypoint above 4000'. If not its time to select speed and change climb gradient.

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