When Adequate Vis Ref isn't published

jrh

Well-Known Member
I'm digging deep into a technical spot I haven't had to think about in a long time and would like some help.

I ran across an airport, Roseburg, Oregon, KRBG, where the Jeppesen takeoff minimums page doesn't have a column for "adequate vis ref" like most airports. It only has ceiling and vis based on aircraft performance or climb in visual conditions.

Why is this? Obviously there are obstacles, but I've seen lots of airports with obstacles still have an Adequate Vis Ref column.

What criteria is used to determine when Adequate Vis Ref either is or is not published?

Also, where is the equivalent information on a government chart? I haven't used government charts in so long I've gotten rusty with them. I'm familiar with the Takeoff Minimums/ODP publication from the government, but I can't find any mention of Adequate Vis Ref minimums in there.
 
I always thought that was an ops specs thing. Google turned up this: https://www.faa.gov/documentlibrary/media/notice/n_8900.393.pdf

So maybe it doesn't need to be charted if it's in your ops specs? I agree that it used to be specified in the Jepps and it's not something I've seen in NOS. I haven't seen a Jepp chart since I retired. I think one could argue that it doesn't need to be charted if it's in your ops specs. I could be wrong, though....
 
Yeah, my operation has OpSpec C079 so I routinely use Adequate Vis Ref, but I've always seen it listed in a column on the Jepp plate as well.

Looking at KRBG, I'm inclined to think there is something about the airport that would prohibit a 135 operator from departing with less than 800-2, but I don't really know. I've looked at the Jepp chart legends and done a fair amount of googling and can't find any details as to why this column would be missing, or if that restricts 135 operators.

Logically speaking, I think it makes sense to go with the more conservative value between OpSpec and charted minimum. For example, my OpSpec allows us to do 600 RVR departures. A runway might be published to allow 500 RVR departures, but we are limited to 600 RVR.

Conversely, our OpSpecs also allow us to do 1800 RVR landings. But if the ILS to an airport only has 1/2 mile published, we are limited to a 1/2 mile regardless of what the OpSpec allows.

The problem with Adequate Vis Ref is I don't know what they mean if a value is absent.
 
Yeah, my operation has OpSpec C079 so I routinely use Adequate Vis Ref, but I've always seen it listed in a column on the Jepp plate as well.

Looking at KRBG, I'm inclined to think there is something about the airport that would prohibit a 135 operator from departing with less than 800-2, but I don't really know. I've looked at the Jepp chart legends and done a fair amount of googling and can't find any details as to why this column would be missing, or if that restricts 135 operators.

Logically speaking, I think it makes sense to go with the more conservative value between OpSpec and charted minimum. For example, my OpSpec allows us to do 600 RVR departures. A runway might be published to allow 500 RVR departures, but we are limited to 600 RVR.

Conversely, our OpSpecs also allow us to do 1800 RVR landings. But if the ILS to an airport only has 1/2 mile published, we are limited to a 1/2 mile regardless of what the OpSpec allows.

The problem with Adequate Vis Ref is I don't know what they mean if a value is absent.
They kind of do list one:
FFABEEAC-2D1E-41E3-9AF9-6D7A319144B0.png
FFABEEAC-2D1E-41E3-9AF9-6D7A319144B0.png

They don’t list standard, in fact they’re a lot higher, hence c079 shouldn’t apply here. But I’ve been out of the game for a bit so check my work.
 
They don’t list standard, in fact they’re a lot higher, hence c079 shouldn’t apply here. But I’ve been out of the game for a bit so check my work.

I see your logic, and I agree. C079 says it only applies when takeoff minimums are standard or less than standard.

That would also explain why I've found other airports that have Adequate Vis Ref missing, but always in cases where the takeoff mins are far above standard, like Aspen and Eagle.

I'm beginning to think the Adequate Vis Ref column (or lack thereof) is basically a reminder of when C079 either does or does not apply.
 
I see your logic, and I agree. C079 says it only applies when takeoff minimums are standard or less than standard.

That would also explain why I've found other airports that have Adequate Vis Ref missing, but always in cases where the takeoff mins are far above standard, like Aspen and Eagle.

I'm beginning to think the Adequate Vis Ref column (or lack thereof) is basically a reminder of when C079 either does or does not apply.

Yea I cant quote the reg but this is how we teach it at our 135. We don’t do anything lower than what’s listed on the Jepp chart even though we are 500 RVR approved


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I see your logic, and I agree. C079 says it only applies when takeoff minimums are standard or less than standard.

That would also explain why I've found other airports that have Adequate Vis Ref missing, but always in cases where the takeoff mins are far above standard, like Aspen and Eagle.

I'm beginning to think the Adequate Vis Ref column (or lack thereof) is basically a reminder of when C079 either does or does not apply.
Yes.

Precisely. This is a shortcoming with the Jepp charts IMO and the way the op specs are structured. It’s confusing, because for instance suppose you are leaving Ketchikan and you can’t make the climb gradient of this departure:

0AF55CBE-1A4D-4884-906B-D28A37B570E8.png

Even though it’s an ILS, it doesn’t matter what the heck the Jepp Plates may say, since you can’t meet the climb gradient you need to use 800-3.
 

You're right, but leave it to pilots to misinterpret a reg.

I've heard some pilots say since the reg says to follow the Part 97 minimums OR the OpSpecs, you can depart below the published mins with adequate vis ref. In other words, follow the Part 97 minimums unless you are fortunate to have OpSpec C079, in which case you can declare you have adequate vis ref, yell Send It! and slam the throttles forward.

I disagree with this interpretation, but pointing out how two pilots can look at the same reg and come to drastically different conclusions.
 
Yes.

Precisely. This is a shortcoming with the Jepp charts IMO and the way the op specs are structured. It’s confusing, because for instance suppose you are leaving Ketchikan and you can’t make the climb gradient of this departure:

View attachment 63346
Even though it’s an ILS, it doesn’t matter what the heck the Jepp Plates may say, since you can’t meet the climb gradient you need to use 800-3.
We can do 1800RVR by meeting the climb gradient for standard mins. The lowest mins for an approach back in. KTN lacks center line lighting and a mid field RVR so 1800RVR is it for the multi crew twins as well.. unless you are a certain freight operator.
 
Not much to add, but, I used to make instrument charts for Lufthansa (Lido) and if Jepp is anything like them, they just take the government charts and convert them to “their” format. Not creating any or modifying of source material data.
 
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