… specifically about the autopilot requirement to 80% of DH, which isn’t clear to me from that note.
The 80% DH AP engagement may be a cary-though from previous requirements, particularly from CS AWO defining the equipment standard.
Previous regs limited Cat II manual to 400m, but if flown with AP a lower value (350?) could be used - provided the lower coupling height had been demonstrated.
The rationale was that the visual segment would have increased with reducing height - not necessarily true for all fog types.
The lower height involved AP accuracy, stability, and nose down failure recovery loss of height (may vary with auto trim up if autoland capable).
Another confusing intermixing of operational and equipment requirements.
The note essentially mandates the use of AP to 80% DH in order to claim the lower RVR; this was not as clear in previous regs.
Lower RVR with autoland may relate to failure cases (CS-AWO) together with the operational procedure associated with the failure - continue with manual landing or mandated GA; with potential for further confusion with AP failure at DH, but when using the lower RVR !