Should the ICAO FPL be addressed to each U.S. Flight Information Region (FIR)/ARTCC?
Domestic-only ICAO FPLs and international flights which remain in North America (i.e., destination Canada or Mexico) should only be addressed to the departure US FIR/ARTCC. International ICAO FPLs should be addressed to the departure US FIR/ARTCC only, domestically, and to each FIR IAW Doc 4444 instructions.