Why turn off pitot tube heating?
I'm not sure what kind of airplane that you are flying in the simulator, but the checklists for jets typically do have you turn the pitot heat on just before takeoff and leave it on until after landing, just so that this is less likely to happen.



Update: I found a French checklist for the Caravelle and it says to turn on the pitot heat before takeoff:


  Rechauffage Pitot.....MARCHE