John Collins
En-Route
KBUY, KGSO, and KINT are all within the uncharted Atlanta center surface area, so any flight plan filed from KBUY would be accessible to any controller tied into Atlanta center. KBUY is situated within the charted Washington center airspace, but gets its flight plans delivered through KGSO TRACON which is tied into Atlanta center. So if you contacted a controller who is part of Washington center or any TRACON/tower tied into Washington center and asked for a clearance, they would not have access to the flight plan. Undoubtedly this exchange of responsibility for flight plan handling from Washington Center to Atlanta Center is so that nearby KGSO TRACON has access to the KBUY flight plans and it makes sense to be the handling facility in spite of the charted Center Boundary.