Jammed stab...most airline guys DO use a plotting chart (accepting that there is a significant minority that don't). Your question should be answered in reverse.....If you had a Gross Navigational Error leading to a TCAS event (not as uncommon as they should be) would the subsequent investigation prove your system was certified. Is the app certified, is the method of verifying no corruption of data when transferring from flight plan to app verified. What is the contingency procedure for signal failure (which I have seen plenty of times with ipad loction).BTW...not denying this is the probably going to be the way forward....but in my company ipads are not certified for in flight use as primary aircraft equipment.