Someone who knows explain RVR.

[siucavflight]

As it pertains to 121 operations. I know that if you are inside the FAF and RVR falls below the required for landing, but does it have to come back up in order to land?
And what about RVV?

 

[ksu_aviator]

You can continue (once inside the FAF) and you can land provided, in your observation, that you believe you have the landing minimums. It is not uncommon for RVR to be wrong, it is a machine and it is only observing one very small area. However, you might consider that if anything ever happens you'll have to find a way to prove that the RVR was wrong and you where right.

 

[charter dog]

Beat me to it!

 

[propsarebest]

You can continue (once inside the FAF) and you can land provided, in your observation, that you believe you have the landing minimums. It is not uncommon for RVR to be wrong, it is a machine and it is only observing one very small area. However, you might consider that if anything ever happens you'll have to find a way to prove that the RVR was wrong and you where right.

That's all fine and dandy, but RVR is controlling, meaning if it is reporting 1100 1100 and 1100, and u think its more than 1/4 mile,u still cant land.

 

[Guitar rocker]

That's all fine and dandy, but RVR is controlling, meaning if it is reporting 1100 1100 and 1100, and u think its more than 1/4 mile,u still cant land.

Not so if inside the FAF....refer to KSU aviator above. He's got it right. Like he said, if anything happens to yah though, you'll need a good lawyer.

 

[CRJDispatchKid]

...and you only need the touchdown RVR above 1200 feet (CAT I) to begin the approach. The midpoint and rollout can be below, and you are still legal to shoot an approach. RVR is always controlling.

Here's what you're looking for from the FAR (121.651):
(c) If a pilot has begun the final approach segment of an instrument approach procedure in accordance with paragraph (b) of this section, and after that receives a later weather report indicating below-minimum conditions, the pilot may continue the approach to DH or MDA. Upon reaching DH or at MDA, and at any time before the missed approach point, the pilot may continue the approach below DH or MDA if either the requirements of §91.175(l) of this chapter, or the following requirements are met:

blah blah blah

 

[Princedietrich]

The key word here is flight visibility. Once you're inside the FAF, it doesn't matter what the RVR or the reported visibility drop to. You can continue the approach all the way to DH or the MAP and then act upon whatever flight visibility conditions you find there. Flight visibility can only be determined by the pilot.

In other words, if you get to DH and you see the rabbits or the approach lights, go down to 100 above TDZ. When you get there, if you see REILS or a row of green lights in front of you, land. If anyone questions you, all you have to say is that you had adequate flight visibility as required by 91.175

 

[A Squared]

That's all fine and dandy, but RVR is controlling, meaning if it is reporting 1100 1100 and 1100, and u think its more than 1/4 mile,u still cant land.

I beleive that this is a myth. I have looked through the regs on several occasions, and I have never been able to find anything which supports this. Could you supply a reference?

 

[Sampson]

I beleive that this is a myth. I have looked through the regs on several occasions, and I have never been able to find anything which supports this. Could you supply a reference?

Its in the Ops Specs for the individual Airline. It also depends what Category your A/C is on how low you can go.

 

[ksu_aviator]

91.175
(c) Operation below DH or MDA. Except as provided in paragraph (l) of this section, where a DH or MDA is applicable, no pilot may operate an aircraft, except a military aircraft of the United States, at any airport below the authorized MDA or continue an approach below the authorized DH unless—
(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

Most 121 and 135 carriers operate using this rule. I don't know of a rule that superscedes this particular regulation.

§ 121.567 Instrument approach procedures and IFR landing minimums.

No person may make an instrument approach at an airport except in accordance with IFR weather minimums and instrument approach procedures set forth in the certificate holder's operations specifications.

So you'll have to consult your ops specs to see if your company restricted landings to ground observation visibility or (if omitted) you still operate on 91.175