Originally Posted by IO540
If one can do a popup clearance and then fly around IFR for hours, I'd be interested in knowing how it works. Not saying it can't be done, but it won't make one very popular
Yes, you can do it with the phrase "I wish to file an airborne flight plan". A Google search for that phrase should give you the details. In the UK I guess you'll usually get passed to London Information to take the details. I've only needed to use it once myself when a Z flight plan went missing on a flight from Sicily to Corsica and the controller insisted there was nothing in the system. Having already taken off VFR and flown a fair distance from the departure airfield, I filed a new airborne flight plan with the Sicilian sector controller. You're right - it's a long winded process and doesn't make the controller's day.