Project Magenta - Unofficial > Airbus Software - Discussion

What happens if I enter block data before route?


Preferably I would like to know what happens in the *real* MCDU interface, but it's OK if you can only advise on simulator version (but please do specify whether you are talking about real or simulator, in case there is a difference... which it seems there often is!).

So my questions are:

1. What happens if I enter the  block data in INIT B before entering route in INIT A?  The system would be unable to compute a fuel prediction, so I am wondering how it responds if I tried to do that.

2. What happens if the amount I specify at block is not sufficient to complete the selected route?  Will I get a warning?  What does the fuel prediction look like in those circumstances?

I would appreciate any help that can be offered on this.  I can't find anything in the Airbus manual that covers these sorts of situations that would never arise with a trained pilot.  But I want to cover situations where the user does not even know the meaning of the data they are entering.

Boeing Skunk Works:
Send this member, dodiano, a PM or e-mail. He is an Airbus pilot.

Trevor Hale:
Hello Nevart,

I guess I don't quite understand why or what "Block Data" you would be entering into the perf or F-Plan Page.  As far as I know, Your block time is the time from start up, taxi, to takeoff. so what Block information would you be trying to enter into the route. (Your reserves would easily compensate for longer block times)

But as far as Project Magenta is concerned "Simulator Software" if you enter a route that requires more fuel then you have on board, or "Programmed" into the sim you will get an "Unable Cruise Altitude" message in the scratchpad.  when you check your Fuel at ETA in the Progress Page you will also see an EAT Fuel of (XXXXX) the brackets mean negative.  If I am not mistaken.  It has been a long time since I have seen the Airbus MCDU as I am now a Boeing Buff, but still the principal in the software should be the same.

Perhaps someone else can jump in here, or maybe I am just misunderstanding what your looking for for an answer.


Thanks for the advice.  Actually the confusion about "block" is just a difference between Airbus and Boeing terms.

What I am referring to here is actually a data field on the INIT B page (when you press INIT and then the horizontal slew keys to go to the next page), and they call it "BLOCK" but it doesn't actually have much to do with what we think of as block time if we are flying.

It basically translates to "fuel at blocks", and we get formula: gross TOW = ZFW + Block.

The computer then calculates the landing weight and tries to make a fuel prediction based on the selected route.  But I was not sure what would happen if a route is not selected or if an insufficient fuel quantity is specified. 

I mean that it might return an error, or it may give a strange prediction, or it may simply accept the bad entry but not make any response at all.

The manual does not cover these scenarios because there is an assumption that the pilot will know better than to do something like that.

As for Proj Magenta.... how faithfully is it reproducing the MCDU?  Is it something that you are involved with personally as a developer?

I have found that nearly all "simulator" programs that include the MCDU do not faithfully reproduce the functionality accurately enough.  So I would be happy to help and share my own research if you wish.

Trevor Hale:
I understand better where you are coming from.  I can assure you that the Project Magenta software is accurate enough that Airbus themselves uses it, and so do many other flight training establishments.

Then if what you say is true and you enter incorrect Block information, You will get the message in the scratchpad that states unable cruise flight level.

We are happy to have your input, however Our Project Magenta forums are unofficial and really are only in place to help people with their software setups and configuration.  If you wish to speak directly to the Project Magenta team, perhaps you should drop them an email.

Best regards,



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