ILS Freq is the same for Cat I, II, III. How does the autopilot know which CAT to use?
It always shows CAT 3 dual although I would have said that it shouldn’t. A BARO minimums entry should give CAT 1. A single autopilot ILS with a RA minimums should be CAT 2 and dual autopilot with RA 0 should be CAT 3
If a plane is capable of CAT III landing it will use it by default. If CAT III is not required or prohibited because airport is not equipped or the pilot is not qualified, they will disconnect AP way before the plane descends to CAT I minima and land by hand. There is no need to have different configurations for CAT I, II and III landings. Boeing AP works the same.
3 Likes