*** NO LONGER APPLICABLE. Unfortunately, the MIRAMAR Landing Challenge was removed with WU7 ***
Once you have 4 hours+ flight time on your profile, you can do the MCAS MIRAMAR Landing Challenge which appears on the top left tile on the Main Menu (where the Discovery Flights usually are) to finally get this on Xbox. My achievement didn't pop right away, though. For some reason it popped while I was checking the progress on an update in the content manager.