Adequate Vis Ref?

[Rally]

I have read about adequate vis ref in the Jepp manual but I still don't get what this is? I have never seen it in NACAs! Anybody have a good explanation of what this is and when you use it. (it is posted under TO mins for each airport)

Thanks

 

[TransMach]

Mate,

I don't have the guidance documents here at home, but if memory serves me:

"Adequate Visual Reference means the runway surface is marked, or colored in such a fashion that the flight crew has constant visual reference to the forward line of travel throughout the takeoff roll" ... now that said, it doesn't mean much.

TransMach

 

[midlifeflyer]

It easy to look for regulatory definitions for everything, but I think that "adequate visual reference" is one of those "English" phrases. Although in some cases the FAA gives us some absolite imnimums (such as 91.175(c) for IMC landings), it pretty much means, "you can see enough out the window to know what the heck you're doing and where you are." Pretty subjective and if you have an accident, you take the risk of being wrong.

 

[TransMach]

Mate,

I was thinking about my basic indoc class at CAL back in the late 80s. The example was:

1) Runway with runway edge lights. You can see the centerline, you can see the edge lights, you have an adequate visual reference.

2) It snows, There's a 1/4 inch of snow in the runway so you can't see the centerline. You still have the edge lights, can see them clearly, so you still have an adequate visual reference.

3) The airport comes along and plows the runway covering up the edge lights. You can't see them now but you can see the runway centerline, you still have an adequate visual reference.

4) Bad news, it snows more and puts another thin blanket of snow on the runway surface. Now the edge lights are burried in snow and the centerline marking is covered in snow. You no longer have an adequate visual reference.

That's how it was explaned to me, yo these many years ago.

TransMach

 

[Rally]

The adequate vis reference value on most charts is like 1/4 mile. How can they say that takeoff minimums for 135 or 121 are a 1/4 when everyone knows that its 1 mile (or the DP) and the RVR or vis for the approach back into that airport.


What am I missing here?


Thanks

 

[Singlecoil]

The adequate vis reference value on most charts is like 1/4 mile. How can they say that takeoff minimums for 135 or 121 are a 1/4 when everyone knows that its 1 mile (or the DP) and the RVR or vis for the approach back into that airport.


What am I missing here?


Thanks

You're missing quite a bit. You are thinking of "standard" takeoff minimums, which just about every 135/121 carrier does not use. With 1600 or a quarter mile and "adequate visual ref" you can take off anywhere. You can even go lower with things like centerline lights, more than one transmissometer, high intensity runway lights, etc. With various combinations of that equipment you can takeoff with as little as 500 RVR but that also requires a SMGGS program in use at the airport. You don't have to have landing minimums, either. If the current vis is lower than landing minimums, you merely have to file a takeoff alternate that is within one hour on one engine in still air.
In a nutshell, 1/4 mile and you are good to go, but you'll have to file a takeoff alternate. Less than that, you have to make sure the runway has additional equipment, mainly RVR's and centerline lights.

 

[Rally]

Yea your right I was mixing my 135 job with others. At mine it was standard or the approach in use. No takeoff alternate.


Thanks!

 

[Hugh Johnson]

Part 91, "If I can see to taxi I can see to take off."

My part 135 operation, trained at FSI for 500 RVR take off and approved by POI.

Good luck!