Sorry, I'm easily confused, but before I start I'd point out that I'm an EASA-lander so I'm used to doing things the way the likes of Radu described.

So are you saying you would continue an approach beyond the Approach ban point/1000' aal/FAF as appropriate, despite the ATC reported visibility being less than minima, in order to do your own assessment of "in flight visibility" at DA/MDA?

No, I wouldn't. That would not be legal under Part 121 regulations. (It would, however be legal if I were not operating under Part 121 or 135) . However, if I was advised that the reported visibility had decreased below minimums *after* I had progressed the FAF, I could legally continue the approach and land if flight visibility was above the minimums.

In FAA world, reported visibility is controlling for beginning the approach (Part 135) or continuing the approach beyond the FAF (Part 121) but flight visibility is controlling for descending below MDA/DA and landing.


If you find this confusing, that's because it is. But keep in mind that there are certain situations where reported visibility may be very different than flight visibility. One example might be a situation there is a localized fog bank in the vicinity of the observers position, but other parts of the airport are in the clear. Another example is blowing snow. Blowing snow tends to affect RVR systems very differently than fog and precipitation. I have on more than one occasion, held at the outer marker in clear conditions with the entire runway in sight, but unable to go past the FAF because the measured RVR was below the published minimum due to blowing snow. Those are extreme examples, but the point is the FAA's regulations are written to allow for the fact that flight visibility is not the same as reported visibility from a ground observer.

Ah, OK, thanks for the clarification and the background info..

Ha! Thanks for the clarification. One simple word changed & it makes a lot of difference. I think I get it now...

I'm still left wondering how is the FAA expecting to enforce this? "Yes, your honor, the RVR was only reporting 100 meters, but I had a flight visibility of 8 miles"

To quote Ernest K. Gann

Rules books are paper - They will not cushion a sudden meeting of stone and metal

Surely a certain amount of pragmatism has to be applied. Regardless of the rules, anything other than an instant decision whether a safe landing can be made is dangerous. If you are interpreting the rules so much that you are adding complexity at a critical time, the rules have failed. The decision to go around should have been built on the way to minima, when you get there it is a simple Land or Go around. If it's marginal and you don't think you like it, throw it away, don't wait until 100ft regardless of the rule book. If there is a CAT 2 or 3 available, try that on the next one, if not, it's not your day, divert.

I'm also an EASA operator but I think common sense is universal.

Safe flying

PK

True, it would be difficult to enforce, but it doesn't seem any more or less difficult to enforce than having the required visual references. ( "Yes your honor, I had XXXX in sight at DA" )

Really, it seems like your system makes more sense, if I understand it correctly. ie: Start the approach based on reported visibility, decide to continue below DA based on visual reverences only. Having the decision to descend below DA be based on visual references *and* flight visibility, which may be difficult to determine, and may differ from the visual references introduces a grey area, which leads to questions like the OP. As Peacekeeper pointed out, it adds complexity at a critical time.