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HP1973

Error/MCDU not calculating descent (2)

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Ok, my previous thread was closed before I could to provide more feedback.

 

Anyway, I went to the tutorial as advised (Volume 6) and followed until page 45, however the same thing happened (screenshot attached): as per flight plan, four minutes before the runway I am still at FL201!?

Thinking that I may have entered the flight plan wrong, I then loaded CO Route LOWILFMN01 only to find the issue still there. As per table on page 45, T/D should be much earlier?

 

I have some experience with the [also virtual] 737 FMC and i had never seen this, could somebody give me pointers what may I be doing wrong? I am really looking forward some sim hours on the 320.

 

BTW, I afterwards tried deleting the MANUAL waypoint and the DISCON - which created a smooth LNAV - but VNAV still looks more like one of a stone brick than a modern jetliner.

 

MCDU VERT PROFILE.JPG

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59 minutes ago, HP1973 said:

Ok, my previous thread was closed before I could to provide more feedback.

 

Anyway, I went to the tutorial as advised (Volume 6) and followed until page 45, however the same thing happened (screenshot attached): as per flight plan, four minutes before the runway I am still at FL201!?

Thinking that I may have entered the flight plan wrong, I then loaded CO Route LOWILFMN01 only to find the issue still there. As per table on page 45, T/D should be much earlier?

 

I have some experience with the [also virtual] 737 FMC and i had never seen this, could somebody give me pointers what may I be doing wrong? I am really looking forward some sim hours on the 320.

 

BTW, I afterwards tried deleting the MANUAL waypoint and the DISCON - which created a smooth LNAV - but VNAV still looks more like one of a stone brick than a modern jetliner.

 

MCDU VERT PROFILE.JPG

 

 

1. Which simulator?

2. Which Aircraft?

3. Are you aware that, unlike Boeings, the altitudes shown on the Flightplan page are not the actual altitudes per se?  You have to go into the Lateral Revision page to see the actual restriction.

4. Discos can cause all sorts of issues with VNAV.

 

 

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And as Dave mentioned, forget what you know from your Boeing. The Bus is totally different.

Which altitiude did you díal in before initiating the descent

And did you initiate the descent at all? This has to be done manually in the Bus in contrary to a Boeing.

You really have to follow the tutorial exactly step by step. And again, forget what you have learned/are used to do with a Boeing.

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17 hours ago, DaveCT2003 said:

 

 

1. Which simulator?

2. Which Aircraft?

3. Are you aware that, unlike Boeings, the altitudes shown on the Flightplan page are not the actual altitudes per se?  You have to go into the Lateral Revision page to see the actual restriction.

4. Discos can cause all sorts of issues with VNAV.

 

 

Hi, I stated my simulator (P3D 2.5) and the aircraft (Aerosoft A320) on the thread that was locked yesterday.

About #3, I am not sure i understood: I am talking about the numbers shown under the SPD/ALT column on the F-PLN page; I understood that here you should be able to see the expected altitude at each waypoint based on the MCDU calculated vertical path. Are you saying that the numbers on the screenshot may actually be correct/expected (20,000+ ft) so close to landing?

About #4, i hear you; thats why as I mentioned earlier I removed the discontinuities but the numbers didnt change significantly, I also tried a totally different origin/dest with a different plan without discontinuities and I see the same issue.

 

 

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Just now, HP1973 said:

Hi, I stated my simulator (P3D 2.5) and the aircraft (Aerosoft A320) on the thread that was locked yesterday.

 

I'm sorry, I don't believe I saw your thread yesterday, thanks for letting us know.

 

2 minutes ago, HP1973 said:

About #3, I am not sure i understood: I am talking about the numbers shown under the SPD/ALT column on the F-PLN page; I understood that here you should be able to see the expected altitude at each waypoint based on the MCDU calculated vertical path. Are you saying that the numbers on the screenshot may actually be correct/expected (20,000+ ft) so close to landing?

 

I understood you, and no, what I'm saying is that those numbers are dynamic and will change based on many difference factors including aircraft performance, the influence of wind speed and direction, aircraft weight (fuel burn or throwing the occasional passenger off the aircraft... lol).  They are not static / fixed as they are in a Boeing, for the actual crossing restrictions you have to look at the Lateral Revision page.

 

Regardless, the aircraft you are using had a very good VNAV but it's not nearly as good as the one in the Airbus Professional series.  I say "had" because that aircraft has been out of development for over 10 years now. 

 

One thing you can do is to ensure that all required STAR waypoints and crossing restrictions are entered into the MCDU. This will help to tighten up the VNAV and associated altitudes.

 

Best wishes!

 

 

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8 hours ago, mopperle said:

And as Dave mentioned, forget what you know from your Boeing. The Bus is totally different.

Which altitiude did you díal in before initiating the descent

And did you initiate the descent at all? This has to be done manually in the Bus in contrary to a Boeing.

You really have to follow the tutorial exactly step by step. And again, forget what you have learned/are used to do with a Boeing.

 

Hi, MCDU not equal to FMC, thanks, noted.

 

I haven even left the gate yet - i'm trying to follow the tutorial but still stuck at page 45 (preparation) because of this.

I guess that the next step is just ignore for the moment the SPD/ALT column, finish preparation and actually get that bird into the air, I will do that later today and revert.

 

Worst case, i can add spoilers, gear, RAT or even open few doors and windows shortly after T/D!

 

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7 minutes ago, HP1973 said:

Hi, MCDU not equal to FMC, thanks, noted.

 

Ah, well...

 

Boeing has an FMC (Flight Management Computer) which is a black box in the aviation bay (not on the flight deck). The input/output device to enter data into the FMS is called a CDU (Command Display Unit) and as you know it is located on the flight deck.  The larger system on Boeing aircraft are often referred to as the FMS (Flight Managment System) and contains many other modules.

 

Airbus has a FMGS (Flight Management Guidance System) and it's also a blackbox and it contains many other modules as well.  Airbus called it's input/output device an MCDU.

 

Boeing refers to the main/autopilot panel as a MCP (Main or Mope Control Panel), on Airbus it's an FCU (Flight Control Unit).

 

I hope this is helpful!

 

 

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7 hours ago, DaveCT2003 said:

 

I hope this is helpful!

 

 

Thanks again for the detailed explanation, I actually meant to acknowledge I understood the difference between FMC/MCDU, but extra info never hurts.

 

So, I just completed my first flight and I must say it was excellent, it may be true you guys havent written a new line of code in 10 years, but you evidently did an awesome job right from the beginning.

I dont know at which time VNAV corrected itself, but sometime after T/O i checked again and the numbers were like I expected, the bird did a smooth flight all the way to the asphalt on the other end.

 

Question: is the excellent copilot/checklist experience the contribution from your partnership with FS2Crew, or is there even more? I ask because I noticed that the configuration utility has a FS2Crew checkbox that is not yet selected. 

 

 

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31 minutes ago, HP1973 said:

Thanks again for the detailed explanation, I actually meant to acknowledge I understood the difference between FMC/MCDU, but extra info never hurts.

 

So, I just completed my first flight and I must say it was excellent, it may be true you guys havent written a new line of code in 10 years, but you evidently did an awesome job right from the beginning.

I dont know at which time VNAV corrected itself, but sometime after T/O i checked again and the numbers were like I expected, the bird did a smooth flight all the way to the asphalt on the other end.

 

Question: is the excellent copilot/checklist experience the contribution from your partnership with FS2Crew, or is there even more? I ask because I noticed that the configuration utility has a FS2Crew checkbox that is not yet selected. 

 

 

 

Yes, it's an excellent aircraft.  Everyone here worked that project years ago.

 

The Copilot is our code, which is basically only script.  It's designed purely to help familiarize you with Airbus operations.  It's our hope that you won't use it after you have become familiar with operating the aircraft.

 

Best wishes.

 

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Yes it's an adapting system. I.e. my extra fuel Mcdu's calculation goes always negative at first but after a while it displays the correct value

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