22/04,
I fly a 767 for a large cargo operator. Been doing it now for 3 decades, plus military flying. I can’t recall an announcement that Low visibility procedures are in effect. It is assumed when the visibility decreases to the point where a Cat 2/3 approach is necessary to land. I preface this with the fact that at many airports, during low visibility conditions, the ATIS may announce that SMGCS procedures are in effect, which changes taxi routings and procedures. As I stated in a prior post, a few weeks ago we planned a CAT 1 ILS into Ontario California. About 15 minutes prior, the ATIS displayed that the RVR was 1000. We checked to see if a CAT 2 or 3 approach was available, it was, so we briefed it, and flew the approach and landed. No announcements by Tower, or special procedures required.
Also some posters asked whether calling Tower to state you’re ready for takeoff is not mandatory. About 90% of all airports I fly to, know where I am, and it’s best to not clog the tower freq with extraneous chatter.