MM, this might be telling you something you already know, so apologies ahead of time if I am (however, I know of people who did get stuck on this). Make sure that the lock symbol in the top corner isn't locked. It protects the display from accidental swipes, but it also gives the impression that the iPad has locked up. Depending on how you have ozrunways set up, it takes either one or two touches on the lock symbol to unlock the screen. Personally, I keep it locked most of the time, only unlocking it when I need to zoom in on something. I think from memory that it only locks when you go into flight mode, so you never see it when you're planning or learning the system.