Flight vis.

But if RVR trumps flight visibility, don't you think that 91.175 would require the reported as opposed to flight visibility?

What's the point of the regs allowing an aircraft (121) to continue past the FAF with lower than required vis only to have them go missed even if they have the runway enviornment in sight? If reported visibility (RVR) is required to pass the DH why do we not hear everyone asking for the RVR at DH? It's impractical. I believe the intent of the reg is to allow a pilot to land if he/she can determine at the DH the required flight visibility (approach light system, runway markings). If you do your homework, you'll know how many feet your approach lighting system/runway markings/etc. are and make the appropriate decision to land or not.
 
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But if RVR trumps flight visibility, don't you think that 91.175 would require the reported as opposed to flight visibility?


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How could it? Many airports do not have RVR reporting. It's pretty clear in that Advisory Circular, that when available, RVR trumps all. Our Ops Specs say the same thing in all references to vis minimums: "RVR is controlling."

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What's the point of the regs allowing an aircraft (121) to continue past the FAF with lower than required vis only to have them go missed even if they have the runway enviornment in sight?

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We too (135), can continue the approach if, when we're past the FAF, the vis drops below mins. Why does that authorization exist? I would suspect it's so you don't have to constantly monitor the AWOS on your approach, if you're going into an uncontrolled airport where the tower isn't giving constant updates. I'm not sure. No matter what, once you get to DH, it's on you to ensure that you have the minimum visbility in order to land.

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I believe the intent of the reg is to allow a pilot to land if he/she can determine at the DH the required flight visibility (approach light system, runway markings).

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I agree, but I don't see what is wrong with requiring a minimum reported visibility before beginning the approach (135/121).
 
No, there's nothing wrong with requiring the visibility up to the FAF. And it is there I agree with you that RVR does trump all. But at DH 91.175 states having the flight visibility. Even at controlled airports tower is not monitoring your approach giving RVR in hopes you'll get it just prior to DH. Every time it's been a factor for me, they've given it when I check in on the approach.

Methinks we're saying the same thing only different ways?

Scenario:

Outside FAF on approach RVR is above mins: continue approach.

Inside FAF, RVR has dropped below: continue approach.

At DH where...
(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and for operations conducted under part 121 or part 135 unless that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

(2) The flight visibility is not less than the visibility prescribed in the standard instrument approach being used; and

(3) Except for a Category II or Category III approach where any necessary visual reference requirements are specified by the Administrator, at least one of the following visual references for the intended runway is distinctly visible and identifiable to the pilot: (I won't go on to list those...):
continue approach to landing.

That's what I'm saying.... is that different than you're saying?
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