Category II and Category III manual
Read the official ruleIf you're operating a U.S.-registered civil aircraft in Category II or III conditions (low-visibility precision approaches), you must have the current approved Cat II or Cat III manual for that specific aircraft onboard. You must follow all procedures in that manual and ensure the required instruments and equipment have been maintained according to the manual's maintenance program.
The operator must keep a current copy of the manual at their principal base of operations and make it available for FAA inspection when requested.
This regulation doesn't apply if you're flying under Part 121 (airlines), Part 135 (commuter/on-demand operations), or operating under management specifications issued under Part 91 Subpart K (fractional ownership). Those operators have their own manual requirements under their respective regulations.
In practical terms: if you're conducting these advanced low-visibility approaches in general aviation, proper documentation and maintenance tracking are mandatory.
*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*