91.175(C) FAF?

bc2209

bc2209

Well-Known Member
I've been trying to figure out a few things regarding this regulation.

I'm hung up on two things:

Specifically "Flight Visibility". Is this literally just what I can see out of the window? Does this mean that the visibility being reported means nothing? How can you quickly identify, say, that you have 2400 RVR (flight visibility) as prescribed for the approach?

Second, if the weather drops below minimums prior to reaching the FAF can I continue the approach at a Part 121 operation?

If I pass the final approach fix and then the weather drops below minimums can I continue the approach under a Part 121 operation?
 
Under part 121 you need the required visibility prior to the the FAF. If it drops after the FAF you can continue. I think most controllers let you know when you have the visibility you need to commence the approach, then let you get to the MAP and either go missed or land.

I run into this quite abit in the northwest. They will let you hold, then as soon as the rvr comes up they tell you and let you commence the approach.
 
ASpilot2be said:
Under part 121 you need the required visibility prior to the the FAF. If it drops after the FAF you can continue. I think most controllers let you know when you have the visibility you need to commence the approach, then let you get to the MAP and either go missed or land.

I run into this quite abit in the northwest. They will let you hold, then as soon as the rvr comes up they tell you and let you commence the approach.
Click to expand...

Any idea where I can find this in the regs or is this an Opspec type of thing?
 
ASpilot2be said:
Under part 121 you need the required visibility prior to the the FAF. If it drops after the FAF you can continue. I think most controllers let you know when you have the visibility you need to commence the approach, then let you get to the MAP and either go missed or land.

I run into this quite abit in the northwest. They will let you hold, then as soon as the rvr comes up they tell you and let you commence the approach.
Click to expand...
"What's your minimum RVR?"
"1800"
"Arcata touchdown zone RVR 1800, direct YAGER, cleared for the ILS..."

bc2209 said:
Any idea where I can find this in the regs or is this an Opspec type of thing?
Click to expand...
See 14 CFR 121.651(b). https://www.law.cornell.edu/cfr/text/14/121.651
 
bc2209 said:
Specifically "Flight Visibility". Is this literally just what I can see out of the window? Does this mean that the visibility being reported means nothing? How can you quickly identify, say, that you have 2400 RVR (flight visibility) as prescribed for the approach?
Click to expand...
Here is a read (PDF) on this topic, I'll have to look for more. That said, I'll defer to @MidlifeFlyer , who has either more information or the means to more quickly and efficiently look it up, than I.
 
bc2209 said:
How can you quickly identify, say, that you have 2400 RVR (flight visibility) as prescribed for the approach?
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My technique: at most places, the layout of the approach lighting matches commonly used mins. (Ex: the first flasher on an ALSF-2 is often 2400' from the runway end identifiers)

I'll say something like "Over the first flasher. Runway in sight. Continue visually." That allows a reconstructable distance and informs that I have the runway environment in sight.

More info here:
http://code7700.com/approach_lighting_system.html
 
Has there ever been any sort of enforcement action by the FAA that questioned a pilot's self-assessment of the visibility at the DA or MDA on an approach where the vis had gone below mins after the FAF?
 
Hacker15e said:
Has there ever been any sort of enforcement action by the FAA that questioned a pilot's self-assessment of the visibility at the DA or MDA on an approach where the vis had gone below mins after the FAF?
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I doubt it unless they have video or something, or the pilot says something stupid in the interview.
 
bc2209 said:
I've been trying to figure out a few things regarding this regulation.

I'm hung up on two things:

Specifically "Flight Visibility". Is this literally just what I can see out of the window? Does this mean that the visibility being reported means nothing? How can you quickly identify, say, that you have 2400 RVR (flight visibility) as prescribed for the approach?
Click to expand...
Yep. It pretty much means "what you see out the window." There are quite a few Chief Counsel opinions and NTSB cases on point. The public NTSB opinion database doesn't go back that far, but the best statement of the rule, from a 1980 case, was quoted in a Chief Counsel opinion in 2010:

"[C]ontrolling visibility is not ground visibility, as reflected by the RVR values, but rather flight visibility, as measured from the cockpit of the aircraft." 2010 Thomey Interpretation​

How do you tell? The same way you report "3 miles right base" when asked to do so by the a Tower or decide you are 1,000' above, 500' below and 2,000' away from the clouds when VFR in Class E airspace. You do your best, using the references available. It's actually not too hard when we're talking about approaches since the runway centerline stripes are 200' apart and there are a number of 500' markers.
Second, if the weather drops below minimums prior to reaching the FAF can I continue the approach at a Part 121 operation?

If I pass the final approach fix and then the weather drops below minimums can I continue the approach under a Part 121 operation?
Click to expand...
Different rule for both 135 and 121. @Autothrust Blue already sent you to the Part 121 reg. 135.225 is the one for Part 135.
 
Hacker15e said:
Has there ever been any sort of enforcement action by the FAA that questioned a pilot's self-assessment of the visibility at the DA or MDA on an approach where the vis had gone below mins after the FAF?
Click to expand...
Yes, there have been. Not that many AFAIK, maybe about a dozen that went at least to a trial to an ALJ, with decisions pretty well split. As one would expect, they all involve incidents/accidents. The evidence tends to be some combination of circumstantial, testimony of other people, and of course, the pilot's own admissions (partial or otherwise) in some cases.
 
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