Originally Posted by cencal83406 (Post 3802653)

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.

Originally Posted by Singlecoil (Post 3802911)

Some airlines have 737"s with HUDs that have rollout guidance. In those, you can continue.

Originally Posted by rickair7777 (Post 3796698)

Practically I agree. Technically you might need published vis.

But after-the-fact there might be situations where it would be beneficial to articulate how you estimated flight vis, if you choose to put yourself in such situations.

Originally Posted by JohnBurke (Post 3862277)

Upon arrival at minimums, the "inflight visibility" is irrelevant. You must see the approach lights to descend, and then the runway environment to descend further.

For a full Cat III, you may not see the approach lights, and probably won't, or much, if anything, of the runway until touchdown. For a Cat I approach, there is no requirement to verify flight visibility at MDA/DDA/DA/DH. Do you have the visual references to land? Then land. Do you not see the visual references? Missed approach. You see it, you call it, you land. You don't see it, you call it, you go. It really is that simple.

Originally Posted by JohnBurke (Post 3862552)

The flight visibility is what you determine it to be, not what is reported by the tower or runway transmisiometer.

Don't disagree at all that's what the inflight visibility FAR is about.

What kind of idiot would later say he arrived at minimums, saw the runway lights and continued down, then saw the runway environment and landed, but didn't have the necessary flight visibility?

Not talking about what you would say , rather what you are required to see if getting a Sim Ride or line check etc. you know the legal requirement of the FAR.

If you arrive at minimums and see the runway lights, you continue and if you see the runway you land. Period. You do not count the bars on the approach lights to determine if you have adequate visibility. You do not attempt to ascertain if you have a legal flight visibility. You see the requisite visual references? You land.

So if you see 2 flashing lights in the mist at two hundred you can continue to 100'? No you can't legally.

What is flight visibility? The ability to see a prominent unlighted object in the day, or a lighted object at night. You see the runway lights, approach lights, red terminatin bars, runway markings, yada, yada, yada? You're seeing that prominent object. You have your visibility. You land. Go figure.

We are not talking about what ifs we are talking about legal requirements and believe it our not they exist for a reason. Usually no big deal if you were to go lower on a ILS to 100' because a TERPS assessment has been done and the visual segment is clear. However remember you can do this on any CAT 1 approach including a non pecision and the approach path might not have the same terrain assessment as a runway with a percision approach thus maintaining the FAR required inflight visibility is essential to ensure you don't hit something. I suggest you read these articles a excerpt is



Nine of the references are on the runway. The approach lights stick out in front of the runway. This means it's entirely possible to reach DA or MDA, be in a position to land, see the approach lights because they're right in front of you, but not have the required visibility to descend further. The approach lights are not a free ride to 100 feet AGL. (The forthcoming FAR 91.176 might be, if you have an enhanced vision flight system, but that's another topic.)






https://www.planeandpilotmag.com/art...or-the-lights/

https://www.ifr-magazine.com/techniq...ger-below-mda/


https://www.ecfr.gov/current/title-14/chapter-I/subchapter-A/part-1

It really is that simple.

Originally Posted by JohnBurke (Post 3862552)

What kind of idiot would later say he arrived at minimums, saw the runway lights and continued down, then saw the runway environment and landed, but didn't have the necessary flight visibility?.

Originally Posted by HIFLYR (Post 3862629)

I used to teach this all the time and sadly the inflight visibility requirement exists for a reason.

Originally Posted by JohnBurke (Post 3864346)

It does. To see the approach lights and subsequent runway environment, and yet we fly cat III approaches to a touchdown without a hint of either one.

Surely when you used to teach "this all the time," you didn't teach arriving at minimums, seeing approach lights, and counting the lights, calculating an in-flight visibility, and then determining whether to continue based on that calculation?

Didn't think so.

Nobody does.

Your only concern upon arrival at minimums and for those still not doing constant descent approaches, the VDP (et al), is whether you see the necessary visual references to continue. That's inflight visibility.

The published numbers are not your required in-flight visibility at minimums, unless you're prepared to lie to me and tell me you have the ability to accurately determine it, passing minimums, to the eighth of a mile and nth degree. No, you're looking for the approach lights and runway environment, like everyone else, and if you see them, there's your inflight visibility. If you don't see them, you're going missed. Again, it really is that simple.

I've yet to hear a briefing that includes "upon arrival at minimums, we'll count the approach lights, calculate our inflight visibility, make a determination if we can continue, and then elect to either press on, or go missed. That would, of course, be idiotic.