Philadelphia was Mountain Air's first hub east of the Mississippi River, and was opened in late 2009. It completed our expansion coast to coast - leaving only the southeastern U.S. as our uncharted continental U.S. territory later filled by opening Atlanta. Philadelphia was also a milestone for our online pilots - we now had operations in an extremely busy airspace that was more often than not covered with ATC service. Mountain Air uses two different areas of the airport for gates. Large aircraft use gates D8, D10, D12, D14, D15 and D16. Commuter aircraft (jets and prop) use gates F2, F4, F6, F8 and F10. The terminal map below shows the locations. Cargo operations use building "C" at the cargo area just north of taxiway K5 near the threshold of runway 9L.