Category III A, B and C

and one more question,
do you know Which are the visual references requiered regarding each type of approach?

The phrase 'Required Visual Reference' is used in relation to the transition from control of an aircraft by reference to flight deck instrumentation to control by reference to external visual references alone. Those visual references, including aids, should have been in view for sufficient time for the pilot to have made an assessment of the aircraft position and rate of change of position in relation to the desired flight path. In Category III operations with a decision height the required visual reference is that specified for the particular procedure and operation. (ICAO Annex 6, and PANS-ATM).

The subdivision in CAT IIIA, CAT IIIB and CAT IIIC is the old/previous ICAO classification of ILS instrument approach procedures. ICAO has abandoned this and now, effective 30 October 2022, EASA does the same. EASA states "Some AFMs may refer to the previous ICAO classification as follows... " and summarises the old A, B and C classification. GM1 SPA.LVO.100(b) refers. It will take some time to completely transfer from the old to the new classification in all relevant documents.

The classification "A, B, C" for the ILS is no longer part of the Chart Published Aerodrome Operating Minima (AOM). YOUR minima will be established according to some criteria during the certification process and should be published to your OpSpec. The FAA published the LOWEST fiseable equipment minima. Is the Operator responsability to use its OpSpec Approved Minima during the Approaches.
https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/a…

thanks a lot for your comments, they are very helpful in our work of training and teaching. we talk about the different operations categories and the visual segments requiered, so now it has changed. I have to modify our texts ans slides. Again, thank you for your kind and informtive comments.