This action establishes helicopter RNAV routes as part of the U.S. air traffic service route (ATS) structure and designates two helicopter RNAV routes (TK-routes) in the northeast corridor between the Washington, DC, and New York City metropolitan areas. The TK-routes are for use by helicopters having IFR-approved Global Positioning System (GPS)/Global Navigation Satellite System (GNSS) equipment. The FAA is taking this action to enhance safety and to improve the efficient use of the navigable airspace for en route IFR helicopter operations.

see full FAA document for details