Hi everyone,

I was wondering about 4 or more runways designation numbers.

Three examples

-LFPG  26L/R  27L/R     why 26 are southern ones and 27 northern ones ?  all are 264°

-KORD  28L/C/R   27L/C/R    why 28 are southern ones  and 27 are northern ones ? all are 273°

-KATL same logic as KORD           KPHX same logic as LFPG

Is there any logical ? or local regulation choice ?

Regards

 

48 minutes ago, ramounch said:

Is there any logical ? or local regulation choice ?

This is the FAA guidance:

 

 

Quote

5. For parallel runways, each runway landing designator number must be supplemented by a letter, in the order shown from left to right when viewed from the direction of approach as prescribed by the following marking criteria. Different labeling patterns than those prescribed below are permissible under certain circumstances as identified in subparagraph 6 below.
a. Two parallel runways having a magnetic azimuth of 182 degrees are designated “18L” and “18R.”
b. Three parallel runways having a magnetic azimuth of 87 degrees are designated “9L,” “9C,” and “9R.”
c. Four parallel runways having a magnetic azimuth of 324 degrees are designated “32L,” “32R,” “33L,” and “33R.”
d. Five parallel runways having a magnetic azimuth of 138 degrees are designated “13L,” “13R,” “14L,” “14C,” and “14R” or “14L,” “14R,” “13L,” “13C,” and “13R.” Other combinations exist for this case. See subparagraph 6 below.
e. Six parallel runways having a magnetic azimuth of 83 degrees are designated “8L,” “8C,” “8R,” “9L,” “9C,” and “9R. See subparagraph 6 below.
f. Seven parallel runways having a magnetic azimuth of 85 degrees – the runways would be designated “8L,” “8C,” “8R,” “9L,” “9C,” “9R,” and “10.” Other combinations exist for this case. See subparagraph 6 below.

6. There are certain runway placements where the surface marking schemes for parallel runways provided in subparagraph 5 above may not be appropriate because their orientation may lead to pilot confusion. For example, the marking scheme recommended for parallel runways on the same side of a terminal is to follow subparagraph 5 above. However, when two parallel runways are separated by a large distance, as by a central terminal or several terminals, it is preferable to designate the runways as non-parallel runways to avoid pilot confusion. [...] In general, the airport operator should carefully choose how to mark parallel runways to eliminate pilot confusion.

Source: https://www.faa.gov/documentLibrary/media/Advisory_Circular/150-5340-1M-Chg-1-Airport-Markings.pdf

 

The guidance is prescriptive. In the USA, the airport operator must designate the six runways with a heading of 093° as 09L, 09C, 09R, 10L, 10C and 10R (as per 5e above).
It follows a logical progression in a left to right reading order.

 

 

 

The only rationale I have for LFPG and KPHX being out of sequence (so to speak) is that the wind direction predominantly comes from the West, meaning that the airport operators designated their primary runway ends based on the direction most aircraft would take-off and land into.

EHAM also designate a runway based on noise limitations at night.

2 hours ago, F737MAX said:

This is the FAA guidance:

Source: https://www.faa.gov/documentLibrary/media/Advisory_Circular/150-5340-1M-Chg-1-Airport-Markings.pdf

...

You're giving me a headache. 🙂