FCU indication

To any (friendly) airbus pilot,

could someone tell me the working of following annunciators on the FCU display :
LAT indication
ALT indication
LVL/CH indication

HDG or TRK indication
VS or FPA indication

The question really is when do they become active and more when do they go off

In many videos i have seen taken in the cockpit the HDG and V/S are always on when HDG/VS (middle indicator) is on and
the TRK and FPA are on when TRK/FPA button is pressed and the TRK/FPA indicator (middle indicator) is on .
I mean HDG and VS or TRK and FPA are on depending on the system used on the FCU.
Is this correct or are there other situations that can turn them off or on?
LAT indication seems to be always on ?
LVL/CH seems to be always on ?
ALT indication seems to be always on ?

Greetz Peter
Belgium

PS : difficult to explain without proper picture
PS : the reason of asking is that Project Magenta software switches the LVLCH only on when climbing to new altitude
or descending
ALT indication on only when target altitude is reached
V/S indication only on when climbing/descending in V/S mode (not in open climb, open descent, managed descent, managed climb)
HDG always on when not in TRK/FPA mode
LAT always on

Ok Will try to answer this:

http://ifsbi.org/public_ftp/fcuonlyclose.JPG

First of all LAT Indication, ALT indication and LVL/CH Indication they never change they are basically Indicators that reflect the functions on that specific window of the FCU... The only ones that change are when you press the spd/mach swithc that you change the window indication from SPEED TO MACH or vice Versa you see it shown on the left side of the FCU window and the dial change from 3 digit number to a 0.XX number when pressed!

On the HDG window it only changes from HDG to TRK when you press the TRK/FPA switch and also the center window indication will turn to TRK/FPA which will be lateral and vertical modes you have selected!

The other that will change is the indication on the VS window Right portion of the FCU window will go to Degrees and will turn to FPA if I recall correctly and it will appear as degrees not longer as feet per minute!

Now the use of TRK/FPA is not an easy one! Basically you never take off TRK/FPA cause you use heading to fly assigned headings by ATC now TRK is used when you are flying a Track for example when intercepting a Radial on a VOR approach where the plane centers towards a signal and makes corrections according to wind to keep that one centered! Now the HDG doesn´t do this you basically follow a heading but the wind could be kicking you out of the desired Track although you have the correct Heading! Also you get the Birdie out which is an amazing tool for flying Visual approaches and is a must for VOR approaches!

Hope this helps!

Roberto

Oh and one more Thing V/S Indication will be on dashes on Open Descent and Descent the plane uses speed to make a descent also a climb it will never appear V/S Unless you select it or you have a mode reverssion to vertical speed.

Regards,

Roberto

Roberto, Excellent explanation. It's nice to have fellow builders, particulary real pilots help the rest of us dreamers:)

Thank You Roberto :)

Well Matt,

I couldnt have put it better.....we are so lucky we got someone like Roberto to answer these kind of questions
At least we can get our simulated world and hardware closer to reality in this way.

Thanks a thousand times Roberto

Peter
Belgium