Need answers fast!

[F16fixer]

question

I'm studying for an interview right now and finding myself looking deeper into regs than normal. You know how that can be.
My question is where in the regs does it say you can continue the approach if the visiblity drops after you cross the FAF? I am looking at 91.175 frontwards, backwards and every other way and can't seem to figure this one out. I see that (c) 2 says that the flight visibilty cannot be less than prescribed in part 97 for the approach to continue down below DH. Nowhere does it say that you can become a human Atis and decide what the visiblity is yourself.

I've always heard people say that if the weather goes below req'd vis before the final app. you can't continue under certain operations, but if it goes bad after the FAF you can continue and determine yourself.

Any clarification would help.

 

[KeroseneSnorter]

Company ops specs are controlling over the FAR's....as long as the ops spec is approved by the Feds. Generally the ops specs are more restrictive than FAR's as is noted in your example. If it has the POI's approval and the almighty FAA stamp of approval in a 135 or 121 operation then it is an FAR as far as you are concerned.

EDIT:Seems you edited out your first question, but this post refers to it, not the weather question.

 

[KeroseneSnorter]

As far as your second question the answer lies in part 121 and 135 regs, I do not have a book in front of me but part 91 does not "disallow it" where as 135 and 121 do. That is the difference as far as legal to start the approach. Once the approach is commenced you are allowed to continue.

As long as RVR is not measured you as the pilot are the only one out there that can make the determination of flight visibility. Even with RVR measured you are still the only "flight vis" guy, but generally the feeling is that if you land when limits are below RVR limits you do not have a legal leg to stand on if something happens. Although under part 91 you are legal to "take a look at anything" regardless of the stated conditions....part 135 and 121 you are not.

 

[F16fixer]

thanks

 

[yzf6]

I see that (c) 2 says that the flight visibilty cannot be less than prescribed in part 97 for the approach to continue down below DH. Nowhere does it say that you can become a human Atis and decide what the visiblity is yourself.

you're the only one that can determine what the flight visibility is, the atis is on the ground. of course you may run into some problems if the feds see you cruising in with 200rvr and claiming you had a 1/2.

edit: nevermind, kerosene beat me to it

 

[ksu_aviator]

Check the FARs Forum, I answered your question there.

 

[F16fixer]

I deleted the first question after it was answered and now have everything cleared up, so thanks everyone and I guess this thread is finished.

See ya

 

[sky37d]

Hope you passed.

 

[A Squared]

I deleted the first question after it was answered

Why? I'm left scratching my head when people do this. Not trying to bust your balls here, but doing that removes whatever your first question was from hte forum. Now, if somone else was wondering the same thing, they'll have to ask the same question, instead of being able to read the thread.

Anyway, about your question on wx andthe FAF. You've pretty much got your answer, but let me add a little that may make it clearer, and will help you later when sorting out other regulatory questions.


You ask:

where in the regs does it say you can continue the approach if the visiblity drops after you cross the FAF

That's the wrong question, regulations very rarely tell you what you may do, they almost always tell you what you may not do. In the instances where a regulation tells you you may do something it is almost always because some other regulation would otherwise prohibiit it.

You should be asking:

where in the regulations does it say that you cannot continue past the FAF, unless the visibility is above minimums.

Then the answer is easy; nowhere. You said yourself that you've examined 91.175 with a microscope. You couldn't find anything, other then hte requirement to have flight visibility above the minimums in order to descend below MDA/DH , so if there isn't a requirement to have minimum vis before proceeding past the faf, then it's perfectly legal to do so.

Do you see the difference between wondering where it says you *can* do something and wondering where it says you *can't* do something?

Anyway, under part 91, you don't need any visibillity to begin or continue an approach, except for continuing bleow MDA/DH. It is perfectly legal to begin an approach and continue the approach right down to MDA/DH with visibility reported zero. It's legal, because there's nothing in part 91 which prohibits it. (it would be in 91.175 if it existed)

Now a couple of things to further clarify. In order to descend below MDA/DH, you must have the minimum flight visibility. It's important to understand that it's flight visibility, and flight visibility can only be determined by the pilot. I have included an FAA Chief Counsel interpretation below which addresses the issue of flight visibility vs reported visibility. Note also that it says Flight Visivbility takes precedence over RVR.


Now, so far the discussion has been for Part 91 only. Thngs are a bit different if you are flying under Part 121 or Part 135 (although ultimately the answer is the same)

Under part 135 you may not begin an approach unless the required weather minimums are reported, 135.225(a)

And under Part 121 you may not proceed past the FAF unless the visibility is reported above the minimum visibility 121.651(b)

However, under both 121 and 135, you are allowed to continue if you are already inside the FAF and a new report shows the vis below minimums. 121.651(c) and 135.225(c)

Ok, this is an example of what I mentioned earlier. 135.225(c) and 121.651(c) tell you that you may do something, but that is only because that action is prohibited elsewhere (in 135.225(a) and 121.651(b) respectively)


Hope that this helps, and that you aren't just more deeply confused.

FAA Legal Interpretation:
March 10, 1986

Mr. Larry K. Johnson

Dear Mr. Johnson:
This is in response to your letter of February 6 requesting an interpretation of Federal Aviation Regulation (FAR) Part 91, Section 91.116.

Specifically, you request clarification of the term "flight visibility" in connection with the requirement in FAR 91.116(c) that an aircraft not be operated below a published decision height or minimum descent altitude if the flight visibility is less than the visibility prescribed in the standard instrument approach procedure being used. The question arises as to whether descent below the DH or MDA can be made when the runway visual range (RVR) is reported at less than the published minimum RVR for the approach but the flight visibility is greater than that minimum.

The flight visibility is controlling. If the flight visibility exceeds the published minimum for the approach, than the pilot may proceed as long as the other requirements of paragraph 91.116(c) are met regardless of the reported RVR. The National Transportation Safety Board (NTSB) has upheld this interpretation in several enforcement cases. However, the pilot's judgment of flight visibility is not necessarily conclusive if there is a question as to the actual flight visibility conditions at the time of the approach. Reported visibility and other evidence of record may be considered by the Federal Aviation Administration and the NTSB in determining the actual flight visibility.


Enforcement action would be taken only in those cases in which the pilot could not reasonably conclude that flight visibility was at or above approach minimums, but the pilot nevertheless proceeded to land or descent below DH or MDA.

Sincerely, David L. Bennett
Manager, Airspace and Air Traffic Law Branch
Regulations and Enforcement Division

 

[F16fixer]

Thanks A Squared,

You usually give an honest answer to someones question and I have used your knowledge in the past. I apologize about the first question. It was concering part 135 single pilot ops while hauling frieght with no autopilot. I thought my ops manual said I needed one no matter what if the auto pilot was inop, but my coworker looked it up and found out otherwise for me. So I realized it was kind of an inside question after I posted it and thought I would erase it.

Take care,

Fixer