When considering cockpit flows and steps during pre-flight, what is a good moment to request IFR clearance that still matches real flight best-practices.
Several sources I came about mention between 15-20min before departure time (There seem to be differences between FAA and Europe though).
For me, the question is, if I do it before, or after MCDU preparation. Before has the advantage that MCDU preparation is probably more final, since the risk that I have to update the flight plan and alike is smaller. On the other hand, for the time I need at the moment, it would be more than 20min ahead of departure. After MCDU departure does not have this advantage, and, additionally, there is not so much to do afterwards, so it would be very tight before departure or I would just have to sit there and wait. In the middle of MCDU preparation is also not nice, because it would mix-up 2 different things at the same time.
How do commercial pilots integrate this steps within their flows normally?
With the advent of ACARS, the clearance request is sent via ACARS and pops up when available. On those days when there was a ground stop at your destination or airspace congestion problems, we would frequently send the ACARS clearance request as soon as we got power on and the flight data in ACARS.
Back in the old days (before ACARS) 15-20 mins was about right to “put your name in the hat” meaning get in the queue for clearance. At hub airports around “push time” for the airlines the clearance delivery frequency got really congested with folks stepping all over each other to get their clearance.
For purposes of the game/sim…perhaps before programming the MCDU.
3 Likes
With default ATC it’s better to wait until you are ready for taxi/pushback. ATC won’t update you with a new runway when wind direction changes. They will send AI traffic to new runway but will force you to depart from the runway they gave you 30min ago.
1 Like
That makes sense, though I should probably have said that I use BeyondATC, so it is not my scenario.
Most airports don’t have your clearance until 20 to 30 min before scheduled time of departure (usually described in the airport text pages), same applies for datalink clearances. I usually aim to receive the clearance as soon as it is available, at airports where you are familiar, you know more or less what to expect and plan for. Still, you need to know what to plan for before starting the cockpit preparation, meaning ATIS (weather, aircraft performance, runway in use), clearance (departure route, initial altitude).
To answer your question, preferably before MCDU preparation. But as with everything, in real life you might need to improvise, set-up the MCDU first, then crosscheck with the en-route clearance when received. You probably know the runway in use already (ATIS), departure routing can be assumed from your flight plan. It can always change of course, but that is also true after the clearance is given 
.