I would like to know, when entering the MCDU data and particularly for the Init A and Perf part, should I wait for the boarding to be completed?

For the perf page yes. Because the weights you get in the EFB are live weights which means they change. So you can either do it before you pushback and start up. Or while you pushback and startup. For the INIT A page you can do that right away. What I do is get in the cockpit. Get the batteries and external power going. Then get the ADIRS on. Next is go into the AOC menu and go to the flight page request the stuff. Then INIT a page request the flight enter flight number, CI and cruise. Then proceed however you do it after that. 

better to wait for ADIRS to align and for boarding to complete, before you fill the PERF page.. the fuel prediction numbers for every way point etc get calculated only after ADIRS aligns.. until then the route navigation that you put into MCDU is incomplete.. 

38 minutes ago, vin747 said:

better to wait for ADIRS to align and for boarding to complete, before you fill the PERF page.. the fuel prediction numbers for every way point etc get calculated only after ADIRS aligns.. until then the route navigation that you put into MCDU is incomplete.. 

The 1st time, I complete the PERF page using the preliminary loadsheet and continue up to where I need to fill in the INIT B page. I stop there. After GSX asks for the fuel quantity, I do an instant load and wait for the final loadsheet, When the LS appears, I complete INIT B, run the TO perf calculations in the EFB using the final LS, and then go back to the PERF page and repopulate it with the new numbers from the EFB. 

So I guess my point is that you can fill in the PERF page the first time through just to get the plane set up "in the ballpark" as we say in the US, because the second time when it gets filled in with the real numbers it will recalculate the fuel prediction numbers all over again.

Wow. Thanks for your wonderfull tips. 

Best regards

Coussini