A new draft Advisory Circular (AC 120-xLS) provides an FAA-approved means of obtaining and maintaining authorization of operations in ground-based Category I, Category II, and Category III landing weather minimums and IFR lower than standard takeoff minimums. This AC reflects “significant revision of information” that occurred in 2011when the FAA removed the definitions of Category IIIa, IIIb, and IIIc operations, and discontinued the use of this nomenclature in subsequent documentation.
The agency stressed that this advisory does not change, add, or delete regulatory requirements or authorize deviations from regulatory requirements. However, the AC does address the operational authorizations formerly published in AC 120-29A and AC 120-28D (which will be cancelled) and any subsequent developments.
The AC notes that some FAA instrument procedures might still retain Category IIIa nomenclature until these procedures are updated or amended, but these definitions are outdated and no longer used for aircraft certification or operational authorization. “Any reference to these terms in this AC is used for historical context,” the agency said. “The general Category III operation definition remains in effect, and is fully described in FAA orders and other ACs.”
This new AC also incorporates information pertaining to international all-weather operations (AWO) criteria harmonization among the FAA, EASA, and other regulatory authorities. Subsequent revisions of this AC will be published as additional AWO harmonization items are agreed upon by these agencies. Also, information is included addressing operations using enhanced and/or synthetic vision systems during AWO operations, as well as operations involving hybrid approach and landing systems. Space-based systems are not discussed in this AC.