1. Category I – An ILS approach procedure which provides for approach to a height above touchdown of not less than 200 feet and with runway visual range of not less than 1,800 feet.

1. Special Authorization Category I – Height above touchdown of not less than 150 feet and RVR not less than 1,400 feet, HUD to DH.
2. Category II – Height above touchdown of not less than 100 feet and RVR not less than 1,200 feet (with autoland or HUD to touchdown and noted on authorization, RVR 1,000 feet).
3. Category IIIA – Approach without a decision height minimum and with RVR not less than 700 feet.
4. Category IIIB – Approach without a decision height minimum and with RVR not less than 150 feet.
5. Category IIIC – Approach without a decision height minimum and without RVR minimum.

Source FAA Pilot/Controller Glossary↗ · checked 2026-08-25