The FAA has updated its guidance for pilots planning flights across international borders to mandate the use of International Civil Aviation Organization (ICAO) flight plans in any case where an international border will be crossed, even if the flight begins and ends in U.S. airspace.
The ICAO flight plan form was updated in November, at which time the FAA said that domestic general aviation operators who use the FAA domestic flight plan form may continue to do so. The agency in March updated the Aeronautical Information Publication, a regulatory document developed in conformance with international standards, to require the use of an ICAO flight plan for any flight that crosses an international border, either VFR or IFR. Changes to the Aeronautical Information Manual were published concurrently.
Most general aviation operators may continue to use FAA domestic fight plans for operations within U.S. borders, though the FAA notes in its online guidance that an ICAO flight plan is preferred in all cases.
ICAO flight plans are required for flights operating with reduced vertical separation minimum (RVSM, used exclusively above 29,000 feet), flights seeking separation based on Performance Based Navigation (PBN) such as RNAV 1, and flights expecting services based on Automatic Dependent Surveillance-Broadcast (ADS-B), according to FAA guidance.