Extracts from “The RAE Contribution to All-Weather Landing“
ICAO ~ 1949 adopted ‘Calvert’ approach lighting pattern.
… airworthiness authorities and airline operators promulgated limiting ‘decision heights’ and RVR below which safe manual landings could not have a high probability of success. Typical figures at this time were 200 feet decision height and 800 metres RVR and, as we shall see later, were classified as Category 1 operations.
All-Weather Operations Panel (AWOP) … considered broad criteria. In 1965 they were adopted by ICAO and remain much the same today (
2011).
Category, Minimum Decision Height (feet), Minimum RVR (metres)
1 200 ft, 800m
2 100 ft, 400 m
N.B. In later years, research has demonstrated and has been accepted for certification, a range of minima depending on type of approach aid, lighting pattern, aircraft equipment and performance. There are wide ranging variations in DH and visibility minima.
https://www.aerosociety.com/media/48...er-landing.pdf