Eh…..let’s not overthink this because someone had a lazy CFII.

 

All, good, but it's not 100' below mins, it's down to 100' AGL.

 

JB is correct that having the approach lights in sight allow you to continue below MDA.
You need a ground reference to continue below 100' AGL, you need to see more than just the approach lights.

 

Yes you can go down to 100' AGL (above TDZE).

The 100' below mins is a common misconception since your typical CAT I has a DA which equates to 200' AGL... so 100' below that is the same as 100' AGL.

 

One can continue to one hundred feet, but that wasn't really the point.

The point was that one does not need to have, or verify, approach weather minimums (ceiling or visibility) when approaching minimums. What's being reported isn't nearly as important as what's outside the window. One is looking outside, or half-in-half-out, depending on one's role for the approach, and at such time as one looks up and sees the required visual references (and acknowledges them, as one's SOP may dictate ("continue," "landing, etc), one isn't asking at that moment in time if the current, up-to-the-second weather is still reporting above minimums, because one is inside the FAF/GSIA and looking for visual references. Those references may be the runway, or simply pre-runway references that allow one to descend a little lower, until one acquires the runway (or must go around).

That was the point. The question regarded whether one must have legal reported weather minimums, when arriving at minimums, and the answer is that one has what one sees out the window, at that point. It was noted by some that one should have the charted (or approved; eg, OpSpec, etc) minimums, but this is not correct. Those were needed to begin the approach; arrival at MDA on a constant descent approach, or DH/DA, one isn't going to (and shouldn't) check weather to see if there are changes; one is looking for the necessary visual references (Except cat III procedures when one may not see the runway before touchdown). So long as the necessary minimums were reported in order to begin the final approach segment, that element of the approach has been satisfied. Upon arrival at minimums, what's seen out the window is the order of the day. What's required and the altitude to which we can go depends entirely upon the procedure, the nature of the approach, in some cases the aircraft, in all cases of certificate holders, the certificate holder's approvals and authorizations, and of course, also the pilot and his or her qualification (and currency).

 

Cat II & Cat III require the weather to remain at or above minimums throughout the approach. However, that’s not the flight crew’s job to determine. If ATC happens to provide an update to RVR while they’re inside the PFAF and that update is below the charted minima a missed approach is required.

 

That's not accurate. Cat II/III approaches may continue if established on the FAS. From a previous post:

This is also explicit in AC 120-118 and OpSpec C060: C060 g. Operating Limitations. "(f) Once established on the FAS, all operations conducted using automatic rollout systems, or FP HUD rollout guidance, may continue if any RVR report decreases below the authorized minimums."

Some countries have specific caveats to this. For example, in the UK, the approach may be flown regardless of the WX/RVR but may not descend below a 1000' AFE if the weather is below minimums. Conversely, the approach may continue if below 1000' and the weather degrades below the applicable minimum.

 

I reread the airway manual and you are correct

we are limited though on the 73 (and I guess the 717 as well) must do a missed on a cat iii if rvr reports below minimums even when established on the FAS.

 

ICAO (a United Nations Agency) Annex 6 to the Convention on International Civil Aviation, Part 1 states in paragraph 4.4.1.2:

"An instrument approach shall not be continued below 300 m (1 000 ft) above the aerodrome elevation or into the final approach segment unless the reported visibility or controlling RVR* is at or above the aerodrome operating minima."

Refer to the country's specifics of operations Aeronautical Information Publication for differences in Approach Bans.

 

The following paragraph to that quoted above, 4.4.1.3, stipulates that (barring alteration by the State criteria), the procedure may be continued once inside the final approach segment (below 300m/1000') if the RVR falls below minimums. In this case, the procedure may be continued to MDA/DH, but is not authorized below (without appropriate visual references required at MDA/DH/DA).

http://www.smolenskiefakty.com/icao_annex_6_part_1_section_4_4.pdf

The crucial element at arrival at minimums continues to be not if meteorological reported minimums are at or above charted minimums, but whether one has the necessary references to continue the procedure below minimums; it comes down to whether one can see the approach or runway lights to either continue, or land.