ORD runway numbers changing
 

Listen up all Channel 9 fans. While not specific to UA of course, they are the only carrier offering flight deck communications. July 5 current runway 9R-27L will be renamed 10R-28L. So if you're coming in and think you're at the wrong airport no need to panic. In August 9L-27R will become 9R-27L. Confused? In November next year (huge maybe) the new north runway will be 9L-27R.

OK. The next question is: Why?

How do they decide on the numbers for runways anyways? I understand the L and R are left and right, but what do the numbers mean?

Add a zero to the runway number and you have its direction. So runway 28 means it is at a heading of 280.:)

If I recall, the #s on the runways roughly line up with the compass heading in which the runway is 'pointed.' You just need to add a 0 to the end of the runway number. For example runway 9 would be headed at 90 degrees or East. The same runway approached from the other direction would be 270, or 270 degrees; West.

Sure they're not just changing them to L-C-R? I know some airports with 3 parallel runways designate a Center runway. Since I believe the ORD shift is temporary until the whole new construction is done (in 20 years?) I wonder why it is not just done that way.

They are not using C because when all is said and done there will be 4 parallel east/west runways. Two on the north side (where they are building a new north field control tower) and 2 on the south side.

I learned something new today and it's not even lunchtime yet!! :) ^

This is true. What I'm confused over...is they're simply changing the runway's numbers from 9/27 to 10/28. But they're not physically rotating the runway 10 degrees. :D

LAX is the same way...the 4 runways are parallel, but they are 7/25LR and 6/24LR. I guess there are special notes on the approach charts to alert pilots that a heading correction is necessary.

Actually, 6:
http://upload.wikimedia.org/wikipedi...S%29_Final.png

SmilingBoy.

Great point. The reason they can do this is that the ORD runways are at approximately 93/273 degrees. Thus, they currently round down to "Runway 9," but they can also round the same runways up to "Runway 10," without physically rotating the runways.

See http://download.aopa.org/ustprocs/20...ms/00166AD.PDF

LAX does the same thing. All four runways are at 249.8 degrees. So they round two down to "Runway 24" and the other two up to "Runway 25."

See http://download.aopa.org/ustprocs/20...ms/00237AD.PDF

Off-topic, but interestingly, sometimes a runway heading DOES change, even when the runway does not physically move. The runway headings are based on magnetic north, not true north. Magnetic north "moves" at a very slow rate. Thus, a runway heading might eventually have to be changed, because its magnetic direction has changed. An example of this is the Palo Alto municipal airport (PAO). It used to have runway 12/30, but a few years ago they had to rename it 13/31, because of the magnetic variation.

emphasis mine: as if it wasn't bad enough already.......so now both sfo & ord will have weather delays on runways with same numbers :eek:

Exactly the reason.

Nope... no special notes. Well... mostly not. The chart does list magnetic heading for the runway. The runway numbers don't exactly line up with magnetic heading anyway and are mainly used for clerical purposes, if you can call it that. I've seen airports where the headings are off by 15+ degrees from magnetic which really screw you up when double checking your instruments after lining up for an instrument departure.

Fair enough...I'd like to think the pilots can get close enough to the big 2 mile piece of asphalt and direct the plane down accordingly. Worst case, when it's about time for touchdown and there are houses and swimming pools directly below, there's the go-around option. :D

You'd think... but then again, there are plenty of cases where the pilots of a flight land at another airport accidentally, such as when NW landed at Ellsworth Air Force Base instead of RAP. Or the numerous planes that try to land on Taxiway T at SEA.