Wind Prediction in the Airbus FMGS: How does it work?
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Wind Prediction in the Airbus FMGS: How does it work?
Greeting everyone,
I'm currently doing line training on the A320 and I'm trying to find out how the FMGS makes fuel and time predictions when we insert wind value in the Init page on the ground. As I did not find anything on the FCOM, I'm requesting your help:
Assuming airport elevation is sea level and cruising flight level is FL350:
In the climb wind phase if I only insert: "230/25/2000": Will the FMGS assume this value from 2000 feet until FL 350 and zero wind condition from ground to 2000 feet?
Second question: still in climb phase, now if at Waypoint Alpha: I Insert: 110/10/2000 and second wind update at Waypoint Kilo: 130/20/4000... Will the FMGS interpolate the 2 different winds in between waypoint "Alpha" and "Kilo" and assume a wind of"120/15/3000?? Or will it assume the exact wind value inserted at A until reaching Kilo then assume wind inserted at Kilo until reading top of climb? Or none of this?
I assume it's the same computation for the wind during cruise phase and descent phase.
Now , I read somewhere on Pprune that during actual flight the FMGS useS for fuel prediction the actual wind (display in the ND) for short distance and still use the inserted wind for Waypoints further away and the distance depending if it is the Thalès or Honeywell FMGS.. Could someone provide the exact value?
Last question: Assuming you fly from EDDL to LFPG and you insert LFPO as alternate. But you do not build up the destination alternate route... Will the fuel prediction( extra time) consider a flight from EDDL TO LFPG and a straight line to LFPO or disregard the alternate and the extra time is only after assuming a go around at LFPG + 30 min holding?
That's it
Thank you for your time.
I'm currently doing line training on the A320 and I'm trying to find out how the FMGS makes fuel and time predictions when we insert wind value in the Init page on the ground. As I did not find anything on the FCOM, I'm requesting your help:
Assuming airport elevation is sea level and cruising flight level is FL350:
In the climb wind phase if I only insert: "230/25/2000": Will the FMGS assume this value from 2000 feet until FL 350 and zero wind condition from ground to 2000 feet?
Second question: still in climb phase, now if at Waypoint Alpha: I Insert: 110/10/2000 and second wind update at Waypoint Kilo: 130/20/4000... Will the FMGS interpolate the 2 different winds in between waypoint "Alpha" and "Kilo" and assume a wind of"120/15/3000?? Or will it assume the exact wind value inserted at A until reaching Kilo then assume wind inserted at Kilo until reading top of climb? Or none of this?
I assume it's the same computation for the wind during cruise phase and descent phase.
Now , I read somewhere on Pprune that during actual flight the FMGS useS for fuel prediction the actual wind (display in the ND) for short distance and still use the inserted wind for Waypoints further away and the distance depending if it is the Thalès or Honeywell FMGS.. Could someone provide the exact value?
Last question: Assuming you fly from EDDL to LFPG and you insert LFPO as alternate. But you do not build up the destination alternate route... Will the fuel prediction( extra time) consider a flight from EDDL TO LFPG and a straight line to LFPO or disregard the alternate and the extra time is only after assuming a go around at LFPG + 30 min holding?
That's it
Thank you for your time.
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The reason why you didn't find that information in the FCOM is because it's not in there. You need to look in the Honeywell FMS Pilot's Guide, Chapter 4 "Preflight", "Flight Planning" subchapter. They gave you one of those guides during type training, right?
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Hello Amadis of Gaul,
Thank you for the reply. Actually I did not get any access to the FMS guide for Airbus... I Google it but can't get a link to download it. Do you know if it is possible to download a soft copy of the Honeywell or Thalès FMS guide?
Thank you.
Thank you for the reply. Actually I did not get any access to the FMS guide for Airbus... I Google it but can't get a link to download it. Do you know if it is possible to download a soft copy of the Honeywell or Thalès FMS guide?
Thank you.
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Pineteam, if you were not provided with this infomation or the Honywell booklet, then I would question the quality of the training you are getting, I hope its not a P2F opperation, but it sounds like it, Good luck.
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Hi Clunckdriver,
I did my training at Cockpit4U in Berlin and no I don't do Pay to Fly and I don't have much respect for those who do it. I'm flying for Air Macau.
I asked a couple of my colleagues and none of them had access to those books during type rating.. So I don't think it's a standard thing..
Thanks Amadis, I will email Cockpit4u then.
But if anyone has a soft copy of the FMS pilot guide, please PM me.
Thanks!
I did my training at Cockpit4U in Berlin and no I don't do Pay to Fly and I don't have much respect for those who do it. I'm flying for Air Macau.
I asked a couple of my colleagues and none of them had access to those books during type rating.. So I don't think it's a standard thing..
Thanks Amadis, I will email Cockpit4u then.
But if anyone has a soft copy of the FMS pilot guide, please PM me.
Thanks!
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Try FCOM...DSC...
AUTOFLIGHT . FLIGHT MANAGEMENT . FLIGHT PLANNING . VERTICAL FUNCTIONS.
Should answer most of your questions .. Or you could ask your line trainers...
AUTOFLIGHT . FLIGHT MANAGEMENT . FLIGHT PLANNING . VERTICAL FUNCTIONS.
Should answer most of your questions .. Or you could ask your line trainers...
Only half a speed-brake
PT:
Do not worry too much. I was trained in Toulouse (the A320 was new to the company) and the FMGS Manual was only "leaked" to us when the Airbus line trainers came back to visit after 6 months from EIS.
If your sectors are long enough as mine used to, you can try inserting some (actually, plenty) P-D waypoints and see what the predictions are like over them on FPL-B.
Meanwhile, send me a PM.
Do not worry too much. I was trained in Toulouse (the A320 was new to the company) and the FMGS Manual was only "leaked" to us when the Airbus line trainers came back to visit after 6 months from EIS.
If your sectors are long enough as mine used to, you can try inserting some (actually, plenty) P-D waypoints and see what the predictions are like over them on FPL-B.
Meanwhile, send me a PM.
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There is a Airbus presentation How to Optimise FMS Prediction which explains FMS wind and temperature models. I am afraid I haven't understood it nor can I attach it for your benefit.
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Although this is not for A320 FMS it might help understand the principle.
https://www.scribd.com/doc/237889229...nd-Entry-MD-11
https://www.scribd.com/doc/237889229...nd-Entry-MD-11
