At a guess, I'd say you are running this code before you view controller has finished all it's setup. When you run this line of code it will be correct, but by the time the view controller.view
gets added to the window
it will be wrong.
Consider setting up your auto-resizing flags or constraints to keep the ad banner in the correct position. Which are you using?
_iAdBanner.autoresizingMask = UIViewAutoresizingFlexibleTopMargin|UIViewAutoresizingFlexibleWidth;
Constraints.... someone else just posted and answer for setting it up with constraints so I won't duplicate their work. :)