Flight vis.

Tokyo007

Tokyo007

Well-Known Member
Ok..

sorry I did a search and couldn't come up with a whole lot..we were having a debate at the school about approaches so here goes:

You're inbound on the ILS 34R KSLC and the mins. on the approach are RVR 1800and they're calling on tower "RVR 600 cleared to land" and atis at the time was 1000RVR when you heard it (insane I know but..stay with me) so you decide to shoot the approach because you can (part 91) and you go down to mins and wow there's the runway you see it right at mins..

question: can you legally land it?.. my thought was no because someone told me if they report lower mins. than the mins on the approach then you cannot land...

now I looked up reg. 91.175.. which says (91.175 c,2 "The flight vis. is not less than the visibility prescribed in the standard instrument approach being used; and.. blah blah")

if you look up the def. of visibility (ICAO) in the aim it's more confusing for me since there are different types...

Chief pilot says you can decend below 100' or if you have it in site and mins you can land.. other cfi's think you can't because the plate shows the "vis." along with what 91.175 says you can't land.. what happens if you crash/incident? FAA blames you because you broke regs? (you landed below mins. you had on your plates at the time)


Sorry this is long but I've been thinking about this.. and I need some input from the jetcareer guys..

(thanks)

Matthew
 
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question: can you legally land it?.. my thought was no because someone told me if they report lower mins. than the mins on the approach then you cannot land...

now I looked up reg. 91.175.. which says (91.175 c,2 "The flight vis. is not less than the visibility prescribed in the standard instrument approach being used; and.. blah blah")


Matthew

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Regs-wise, for you, under 91.175(d), you technially can't land from the approach if the flight viz is less than the viz required.
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Landing. No pilot operating an aircraft, except a military
aircraft of the United States, may land that aircraft when the flight
visibility is less than the visibility prescribed in the standard
instrument approach procedure being used.

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This is sort of dumb, IMO, because If you shoot the approach, which you legally can to take a "look" under 91, that is, commence the approach Why wouldn't you land if you end up seeing the runway environment, as described in 91.175 (i-x)?

For me, I would land no problem in your situation, if I see the runway and determine I can safely make it.
 
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This is sort of dumb, IMO, because If you shoot the approach, which you legally can to take a "look" under 91, that is, commence the approach Why wouldn't you land if you end up seeing the runway environment, as described in 91.175 (i-x)?

For me, I would land no problem in your situation, if I see the runway and determine I can safely make it.

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I agree..if you see it and can land safely you should be able to but it sounds like reg. wise you can't. It's a little confusing.. plus like I said if you tail strike or wing strike whatever what would the FAA say?
 
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This is sort of dumb, IMO, because If you shoot the approach, which you legally can to take a "look" under 91, that is, commence the approach Why wouldn't you land if you end up seeing the runway environment, as described in 91.175 (i-x)?

For me, I would land no problem in your situation, if I see the runway and determine I can safely make it.

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I agree..if you see it and can land safely you should be able to but it sounds like reg. wise you can't.

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If you can see the runway, that doesn't necessarily mean you have the required visibility to land. Look at the runway markings, lights, and approach lights to determine if you have the required visibility. Before you start the approach you should know what you need to see to have the visibility, if you don't see it, you don't land.

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It's a little confusing.. plus like I said if you tail strike or wing strike whatever what would the FAA say?

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If you didn't have the required visibility, they would hand you a violation at the least. They might take your certificate since your violation resulted in bent metal. Along with the general heartache that comes with bending an airplane.
 
Ahhh yes. At Sierra they make us learn the flight visibility like the back of our hand.

It is defined as - The average forward horizontal distance as viewed from the cockpit of an aircraft in flight from which prominent unlighted objects can be seen and identified by day and prominent lighted objects can be seen and identified by night.

I just typed that from memory so it might not be word for word, but the important part is "as viewed from the cockpit of an aircraft in flight". So who then can determine flight visibilty? The answer is the pilot and only the pilot, from the cockpit of an aircraft in flight. So if the approach calls for a certain flight visibily, and you can see that far, you can land.

Be kind of carefull though, because if it is well below minimums and you land claiming that you determined flight visibilty was above mins when it really wasn't, you can still be cited. I heard a story about a guy that shot an approach in a little less than 1/2 mile ground visibility and the approach prescribed 1 mile flight visibility. If I remember the story correctly he even landed safely, but I guess ATC was doubting that flight vis was actually over a mile due to the reported ground vis. Why they cleared the guy for the approach/landing I don't know, but the FAA came after him and he played the "I determined FV was over 1 mile" card and they asked him about a landmark that was on the departure end of the runway that was less than one mile long. When he couldn't describe it they knew he couldn't really have seen that far. I guess it was a pretty signifigant landmark, and actually had he been familiar with the airport probably could have been able to describe it even if he didn't really see it, and they wouldn't have been able to do anything more at that point. But since he couldn't describe it he was cited.

So the moral of the story is, if you can see as far as you are supposed to be able to, you can land. But make sure you can really see that far.
 
good points all of you guys thanks for responding - It should be clear as day but I have a hard time trying to figure this stuff out
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So the moral of the story is, if you can see as far as you are supposed to be able to, you can land. But make sure you can really see that far.

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Yeah. Like I said, real world for me, I'd land if I saw the runway environment, or even if I had just the ALS in sight, I'd continue referencing the 100' rule for precision and press as I saw fit. IMO, 91.175 is a good FAA recommendation I'd consider, but ultimately I'd do what I felt was necessary and safe to effect a landing, since I think 91.175(c)(2) is counter to common sense, if you breakout and can see the runway environment, regardless of what's being called as viz, so I don't really pay too much attention to that part of the reg (and many parts of it, for that matter).

For your ops, Matt, follow 91.175's guidance.
 
NEVER land against RVR.
The FAA doesn't care if "flight" visability is 10nm. The "OFFICIAL" measuring device will win.

PS....If the ceiling is consistant at 100-200 OVC, don't shoot a non-prec app to 500-900 AGL to "take a look," you're not going to see anything. We sat on the ground one night waiting for a release while 3 a/c kept shooting approach after approach, trying to get in.
 
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NEVER land against RVR.
The FAA doesn't care if "flight" visability is 10nm. The "OFFICIAL" measuring device will win.

PS....If the ceiling is consistant at 100-200 OVC, don't shoot a non-prec app to 500-900 AGL to "take a look," you're not going to see anything. We sat on the ground one night waiting for a release while 3 a/c kept shooting approach after approach, trying to get in.

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I don't disagree, however there is no FAR that you'd be busting. No FAR that I'm aware of says anything about RVR, its all flight visibility. So all the FAA can do is just like in my story above, try to prove that you didn't really have the flight visibility. But I do agree that you should never land agains RVR. Simply because the chances of flight visibility being higher that RVR are virtually non-existant, the FAA knows that, and will probably try to find a clever way to prove it like in the story above.
 
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I don't disagree, however there is no FAR that you'd be busting. No FAR that I'm aware of says anything about RVR, its all flight visibility.

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There is under 135/121.

Also, for Part 91, reference AC97-1A

Here is the pertinant part:

c. Visibility Measurements.

Visibility measurements at airports are presently reported in terms of statute miles or fractions thereof and, in case of RVR, in terms of feet. RVR equipment is not capable in all cases of reporting the precise increment of feet equal to the usually reported fractions of a statute mile. RVR reports, when given for a particular runway, are controlling for all takeoffs and landings on, and approaches to, the runway.
 
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IMO, 91.175 is a good FAA recommendation I'd consider, but ultimately I'd do what I felt was necessary and safe to effect a landing, since I think 91.175(c)(2) is counter to common sense, if you breakout and can see the runway environment, regardless of what's being called as viz, so I don't really pay too much attention to that part of the reg (and many parts of it, for that matter).

[/ QUOTE ]Here's the problem, Mike. I'm no TERPS guru, but it's not all about landing. Part of the viz requirements is for obstruction clearance for the missed - so it's done soon enough to permit climb to missed altitude without hitting something.

Besides, going back to the original question, 91.175(c)(2) visibility isn't reported visibility anyway. It's flight visibility - what the pilot sees from inside the cockpit on final, not what the AWOS or tower observer a mile away from the threshold sees.
 
Even though I may be technically legal, I would not shoot an approach if the RVR was significantly less than the minimums. As long as I was ok on fuel, I would go to the alternate because I care more about my long term career than having to use some more fuel and possibly spend the night at a different airport. It is better to not have to explain yourself to the FAA, legal or not.

That said, if the ceiling was broken and vis. was above minimums, I may go ahead and shoot it because there is a chance of breaking out at the right time in a hole in the broken ceiling. Of course if the last few aircraft had to go missed, I would not waste the fuel and instead go to the alternate.
 
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Even though I may be technically legal, I would not shoot an approach if the RVR was significantly less than the minimums. As long as I was ok on fuel, I would go to the alternate because I care more about my long term career than having to use some more fuel and possibly spend the night at a different airport. It is better to not have to explain yourself to the FAA, legal or not.

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What is there to explain? If you're part 91 you can fly the approach, it's not just "technically legal", it is legal, very legal. No one is ever going to question you flying an approach.

You would run into problems if you went below the MDA/DA when you weren't supposed to.

Flying an approach when you know you can't get in is good practice. A missed approach when still in the clouds at DA is a whole different experience from being under a hood.
 
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Even though I may be technically legal, I would not shoot an approach if the RVR was significantly less than the minimums. As long as I was ok on fuel, I would go to the alternate because I care more about my long term career than having to use some more fuel and possibly spend the night at a different airport. It is better to not have to explain yourself to the FAA, legal or not.

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What is there to explain? If you're part 91 you can fly the approach, it's not just "technically legal", it is legal, very legal. No one is ever going to question you flying an approach.

You would run into problems if you went below the MDA/DA when you weren't supposed to.

Flying an approach when you know you can't get in is good practice. A missed approach when still in the clouds at DA is a whole different experience from being under a hood.

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Your right, I should have said I would not fly the approach and land, even if it seemed like the reported RVR was wrong and I did barely have enough visibility. If I was just practicing and intended to go missed, that is a different story.
 
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NEVER land against RVR.
The FAA doesn't care if "flight" visability is 10nm. The "OFFICIAL" measuring device will win.

PS....If the ceiling is consistant at 100-200 OVC, don't shoot a non-prec app to 500-900 AGL to "take a look," you're not going to see anything. We sat on the ground one night waiting for a release while 3 a/c kept shooting approach after approach, trying to get in.

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That was me shooting the approach, i knew you were loving it. Lets give er another shot!
 
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Here's the problem, Mike. I'm no TERPS guru, but it's not all about landing. Part of the viz requirements is for obstruction clearance for the missed - so it's done soon enough to permit climb to missed altitude without hitting something.

Besides, going back to the original question, 91.175(c)(2) visibility isn't reported visibility anyway. It's flight visibility - what the pilot sees from inside the cockpit on final, not what the AWOS or tower observer a mile away from the threshold sees.

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I completely agree with you regards the TERPs stuff, which is why I didn't mention anything about "ducking under" or anything else (which I should've addressed the dangers of). What I was referring to was being in more of a "normal position to land" type deal, then I'd land. No prior to VDP descents, or duck-unders, or anything really out of the ordinary, if the issue is viz only. If I can see the runway, I'll land.

Only reason I mention 91.175 as a good reference as opposed to reg, is because for my ops, that's what it is. The whole "except a military aircraft of the United States" caveat that covers most of that reg. That lets me use what info works in the reg (definition of runway environment, etc), and disregard the chaff. For all other, I recommend following the reg as written.
 
Ok so I think we're all in agreement at least that flight vis. is from inside the cockpit regardless of what tower/asos/awos/atis whatever says so if you "know" you have a higher flight visibility.. and see the runway you should be ok (not that I plan on trying that anytime soon)


... so if any of us are sitting in a *interview* for skywest airlines and they ask that question (the original question) you would answer the same way as you did?

(not trying to drag this out.. just seems like one area they could get you on)

ps-thanks for the reference to the AC97-1A eatsleepfly
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Ok so I think we're all in agreement at least that flight vis. is from inside the cockpit regardless of what tower/asos/awos/atis whatever says so if you "know" you have a higher flight visibility.. and see the runway you should be ok (not that I plan on trying that anytime soon)

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No, actually we're not all in agreement. Yeah, flight vis is flight vis is what you see from the cockpit, but go back and read ESF's and NJA Capt's posts again, and I think you'll see that RVR is the winning choice if it comes down to your word (i.e. flight vis) versus the "official" visibility in case of an incident, accident, or certificate revocation action.

If something happens and the FAA is reviewing your flight, I can almost guarantee that they will use RVR rather than your word (flight vis) as the deciding factor in determining if you violated the FARs by landing.

This was a topic that was discussed during my ATP check ride (with the FSDO, not a DE). His response was exactly what I'm telling you now. If it comes down to some kind of certificate action, the FAA will use RVR as the official determination of visibility rather than take your word for what you thought your flight visibility was.

In the real world if you decide to land when you have the runway in sight, even though RVR is below mins, will you get busted? Probably not unless something goes wrong. Your choice and your butt.
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so if any of us are sitting in a *interview* for skywest airlines and they ask that question (the original question) you would answer the same way as you did?

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They did ask me that question, and I answered the same way. Then they hired me.
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In the real world if you decide to land when you have the runway in sight, even though RVR is below mins, will you get busted? Probably not unless something goes wrong. Your choice and your butt.
bandit.gif


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Key? Don't crump the landing.

I'd venture to say that there might be a number cases where flight viz (slant viz) will be better than recorded RVR. The kicker is, proving your side of the argument to the FAA. You could still be right, could've caught a small break in the WX slant range, but I agree that the Feds likely won't care what the pilot has to say in that case.

What sucks about these sort of situations is for me, if the Feds found out who I was in a situation like this, they legally could cite my ATP, even though I never operate under the priviliges that ATP in a government aircraft, nor am I bound by some of their regs while flying in the same operation.

Key 2? Don't let them know who you are.
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