Big Duke 6:
By my read, there is a difference between XX03 and MMFO. XX03 is airspace not assigned to any country, so it does even have a class of airspace designated. MMFO is assigned to Mexico, RVSM compliance is required FL290 - FL410, hemispheric altitudes are assigned, and the airspace is designated as Class G (uncontrolled) from surface to UNL.
Last edited by Le Flaneur; 10th Sep 2019 at 03:36.