And to throw this into the mix there's exemption 5549. Provides relief from 121.652 of the Federal Aviation Regulations (High Minimum Captain Limitations)... which supposedly allows High Minimums Captains (less than 100 hours in type) to fly an approach to published minimums as long as the company has receive authorization and the aircraft is equipped with an autopilot with approach coupler used all the way to decision height.
Doesn't 3585 say that the conditional language cannot be less than half the required visibility?
Exemption 3585 would not apply to dispatching using the Cat III alternate rules. The visibility reported in TAF's is in 1/4 mile increments, so if you need 600/600/0 for a Cat III approach, you would need the conditional language to be half of that, or 300 rvr, which it could never be since the reports are in 1/4 mile increments, ie vis 0 or M1/4 or 1/4.
My company applies 3585 to High min's Captains simply by using their higher vis requirements for the base calculations. We do prohibit all high min's guys from doing any CAT II or III approaches in accordance with FAR 121.652 (c).
I am confused now. What airplane are you operating that allows for CATlll (autoland) with an engine out? Can't recall whether the 777 could do this or not. I know the L1011 (Non-digiatl AP) could and that was exceptional for the time.