ICAO distinguishes approaches operations based on DH between 'Type A' (DH >= 250 ft) and 'Type B' (DH < 250 ft), which are further divided into subcategories. From the Annex 6 — Operation of Aircraft Part I: a) Type A: a minimum descent height or decision height at or above 75 m (250 ft); and b) Type B: a decision height below 75 m (250 ft). Type B instrument approach operations are ...