Four parallel runways designation

[capricorn23]

Hi all, I have the following question regarding the "title" object.
Let's discuss the LAX and CDG airport case:
-LAX: landing West, the two couples of RWYS (the Southern couple, 25 L/R, and the northen pair 24 L/R have the same magnetic orientation: 251, and therefore the opposite ones, 6 L/R and 7 L/R have 071). The designation is 25s for the Southern and 24s for the northen (and 6s and 7s for the opposite)
-CDG: still landing West, for a similar RWY layout, we have: Southern RWYS 26 L/R (orientation 266) and for the northen, 27 L/R (same orientation).
Now: after all this, knowing that and addition of Ten degrees is added to differentiate the two set of parallel runways, is there any logic in giving "this extra" to one set or another?
Does the "preferential landing direction" (no wind), play a role in this scenario.
Thanks a Lot.

[Check Airman]

In the US, the runways to the north tend to have the lower numbers. ATL, MIA and PHL do that as well. Standing by to be corrected.

*MIA only has 3 parallel runways, but I'm told the designation was changed due to human factors.

[capricorn23]

Thank you Check Airman for your reply.
What do you mean with the "humanum factor" reason for MIA?

[westhawk]

KPHX Phoenix Sky Harbor is an interesting case. 3 parallel runways, with the Southern pair being designated 7L/7R and 25L/25R while the Northern runway is designated 8 and 26. All are within 1/10th deg alignment.

KDEN Denver is different in that it has 6 runways. (12 if you count both directions!) The West runways are 16L/R and 34L/R. The East runways are 17L/R and 35L/R. Then the North runway is 8/26 while the South runway is 7/25.

The point being, I'm not convinced there's any standard or rule applied consistently for US airports. I would expect it may be part of the airport approval process for airports intending to comply with part 139 standards. As such, each case may be decided upon the basis of the study completed as part that specific airport's approval process. IOW, what's considered best for one airport may not be considered best for another airport. There are literally tens of thousands of pages of advisory circulars, regulations and orders related to the subject of airport design and approval, so good luck running down a specific standard or rule!

As such, it seems that it's not safe making any assumptions. Spending some time in cruise reviewing the airport layout and available procedures is time well spent.

[DaveReidUK]

The point being, I'm not convinced there's any standard or rule applied consistently for US airports.

Annex 14 (which of course contains SARPs, not binding rules) simply says that one pair should be designated with the nearest 10° heading and the other pair with the next nearest. But then it also says that runway designator markings should always be 2 digits. :O

Horonjeff et al note that "this type of designation is increasingly being applied to three parallel runway configurations as well".

[eckhard]

I seem to remember that there was provision in the regulations for five parallel runways, as follows in this example:

27R
27CR
27C
27CL
27L

whch I always thought was an accident waiting to happen!

I can’t think of an airport where this was actually used. Does anybody else remember this?

[DaveReidUK]

I seem to remember that there was provision in the regulations for five parallel runways, as follows in this example:

27R
27CR
27C
27CL
27L

whch I always thought was an accident waiting to happen!

I can’t think of an airport where this was actually used. Does anybody else remember this?
Well it didn't come from Annex 14, which would designate 5 parallel runways as either

17L-17C-17R-18L-18R

or

17L-17R-18L-18C-18R

DFW has the first of those two configurations.

[MarkerInbound]

DFW started with 17L on the east side and 17R on the west side. When the first set of parallels was built the east side runways became 17 left and right and the west side runways became 18s. There are plans for a short (by DFW standards) far west runway which would be 18R-36L and the current 18R-36L would be renamed 18C-36C. But there are noise concerns as flights for that runway would go over the center of the town of Grapevine to the north of the airport. And the demand for 6 parallel runways isn't there yet.

[eckhard]

I think the “CL” and “CR” may have been an FAA thing, not Annex 14?

[westhawk]

Annex 14 (which of course contains SARPs, not binding rules) simply says that one pair should be designated with the nearest 10° heading and the other pair with the next nearest. But then it also says that runway designator markings should always be 2 digits. :O

The FAA has done allot over the last 25 years or so in the name of "ICAO harmonization" (at least that's what they used to call it back in the '90s) But some things are not likely to change any time soon.

As more work is put in toward understanding the effects of human factors though, the FAA has been very interested in finding ways to reduce pilot misperceptions as they relate to runway safety and the prevention of incursions. It's been a hot-button issue for quite some time now. Not much seems to work, but they're always trying!

I agree about the two digit runway designations too. It bothers me a little bit when that convention is ignored. :=

[Check Airman]

Thank you Check Airman for your reply.
What do you mean with the "humanum factor" reason for MIA?
When what is now 08L was opened, it was designated 09L. The current 8R used to be 9L, and the runway to the south was 09R.

The story I was told is that people were getting a bit confused, seeing a 9L/C and not readily seeing the 3rd parallel. (Depending on the angle, the south runway can be a bit hard to see if you're going for one of the north runways.)

They were thus renamed as follows:

9L -> 8L
9C -> 8R
9R -> 9

Standing by to be corrected if necessary.

[Smythe]

But then it also says that runway designator markings should always be 2 digits.

Coding nor FMS would accept 3 digit runway designation.

[DaveReidUK]

Coding nor FMS would accept 3 digit runway designation.

I can't see why there would be any requirement for more than two digits in a runway designation, unless there was a need to express its heading more precisely than the nearest (or next nearest) 10 degrees.

[RVF750]

Antalya has three, 36L, 36C, and 36R. Just saying.

[DaveReidUK]

Antalya has three, 36L, 36C, and 36R. Just saying.

Any airport with parallel runways will have those alpha suffixes after the two digits (or one) that indicate the heading. See the above discussion.

[giggitygiggity]

What's the plan for Al-Maktoum, i know that budgets have been cut etc, but wasn't that place supposed to have 6 parallels?

[Smythe]

That is Dubai World Central now....

[Smythe]

I guess it has been renamed again, about the 4th time....when we first looked at this, there were 10 runways, 2 exclusive for the Royal Family

From the plan, you can see how the runway designation fits with L-C-R terminal and L-R

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/1280x720/maxresdefault_c760033a0a4a746887f276b1b85c66870bcc380c.jpg