EASA AIR OPS
Annex I Definitions for terms used in Annexes II to VIII

(13) ‘category I (CAT I) approach operation’ means a precision instrument approach and landing using an instrument landing system (ILS), microwave landing system (MLS), GLS (ground-based augmented global navigation satellite system (GNSS/GBAS) landing system), precision approach radar (PAR) or GNSS using a satellite-based augmentation system (SBAS) with a decision height (DH) not lower than 200 ft and with a runway visual range (RVR) not less than 550 m for aeroplanes and 500 m for helicopters;

(14) ‘category II (CAT II) operation’ means a precision instrument approach and landing operation using ILS or MLS with:

(a) DH below 200 ft but not lower than 100 ft; and
(b) RVR of not less than 300 m;

(15) ‘category IIIA (CAT IIIA) operation’ means a precision instrument approach and landing operation using ILS or MLS with:

(a) DH lower than 100 ft; and
(b) RVR not less than 200 m;

(16) ‘category IIIB (CAT IIIB) operation’ means a precision instrument approach and landing operation using ILS or MLS with:

(a) DH lower than 100 ft, or no DH; and
(b) RVR lower than 200 m but not less than 75 m;