A question to do with runway numbering
 

Please forgive a member of Cabin Crew for intruding on a flight deck forum, but I have been wondering for a while now what the significance of the runway numbers actually are.

For example, at LGW (EGKK) you have 26L&R and 08L&R, but LHR (EGLL) I believe is 25L&R and 07L&R. What is the significance with the runway numbers and how are they allocated?

Regards

They correspond to the magnetic heading of the runway, so Heathrow's runway 26 is on a heading of 260 deg(to the nearest 10 degrees) and 08 being 080 degrees. With the earth's magnetic variation slowly changing every year, the runway number will slowly move from the magnetic heading and will eventually need changing to bring it back in line.

And there are a few variences. In the USA, the drop the preceeding zero, so the runways with a bearing of 040 degreed in JFK are 4L and 4R. L and R obviously means Left and right, you can see a C for centre when there are three eg AMS with 18L, 18C and 18R.. Sometimes they are given different numbers even though they are pointing the same way. Taipei has 05 and 06 depsite their being parallel and LAX has 4 parallel runways which they have numbered 27L, 27R, 28L and 28R.

And although it's obvious to most that the reciprocal of 09 is 27 and the different numbered runways are the same piece of concrete, it can get lost on some. I recall that the officer in charge of the motorised transport at an RAF base overseas once wrote a memo asking that as only runway 04 was ever used (because of the prevailing winds at this airfield were always easterly) could he use runway 22 to park vehicles on!

Taipei has 05 and 06 because there used to be 05L, 05R, and 06. 05R is now a taxiway.

LAX runways are 24L, 24R, 25L, and 25R. Since the rules allow only 3 runways with the same number (L, C, & R), 4 parallel runways must use different numbers, usually paired by those closest together. DFW is similar with 17 and 18.

Many thanks for your quick replies, it all makes sense now :ok:

<<Heathrow's runway 26 >>

Heathrow's runways are 27/09. They used to be 28/10 until the magnetic variation changed slightly. I was on watch the night they changed. They used every vehicle they had to try and shift the runways round... finally I added my trusty old Reliant Robin to the rope and we managed to pull them round in time for the first lander.

Out of interest when do they become 28/10 again?

It should be easy enough to work out... but it's far enough off for me not to have to worry so I've never tried the calculation.

Some enlightened Authorities prohibited the use of 02/20 and would designate the nearer adjacent numbers i.e. 01/19 or 03/21 in order to limit the chance of confusion. Similarly with 13/31.

Adjacent airports also fiddle the numbers so that parallel runways have different ident over the R/T

Too hard to predict that.

However, there's a growing consensus that Earth's magnetic field is about ready (maybe within as little as 100-200 years) to "flip" again -- exchanging north and south poles. That would make 10/28 a more near-term likelihood than 28/10...

Is this a local (or country-specific) prohibition, Air Conditioned? There's loads of Runways numbered 02/20 and 13/31 all over the world.

Crotalo,

I believe the avoidance of (e.g.) 02/20 etc, was the rule in Australia. It may still be, as I see that Launceston (YMLT) has runways 14/32 but the magnetic bearing for 14 is given as 133.

There was I believe, a wartime airfield in England which had a runway 08/27. It was because the runway had a pronounced hump, and somehow when they came to asssess its QDM, they got differnt readings at each end of the runway. I suppose if there's only a (say) 3 deg difference it could happen.
The airfield was in Warwickshire or Herefordshire, I'm not sure which. My old W/O told me about it years ago

I have (sigh!) once built a runway that was bent. I designed it (straight I thought) and my learned colleagues Mi#e and Kev%n built it (bent I discovered). We hid the bend with clever use of bitumen and paint. I won't spoil the fun by saying which runway, but a good number of you have used it already. At least we didn't advertise it by using non-reciprocal runway numbers.

Oh go on OverRun, don't keep us in the dark, which runway is it?:)

It does seem that the 02/20 prohibition is an Australian convention, I believe arising after an accident at Townsville (017°/197°) where some unfortunate soul confused one for the other and ran into one of the lumpy bits that proliferate around Townsville.

Dyslexics visiting Singapore beware! Just about every damned runway here is a 02/20 (or is it 20/02?) :O

Regards,

Old Smokey

I think they'll become 10/28 or thereabouts first.....paleomagnetism students will know what I mean!

This isn't really relevant, but as an ex Herc driver I remember that the secondary runway at Lyneham (18/36?) is visibly bent - the centreline markings actually turn several degrees at the bend point somewhere near halfway along the runway. I am sure it has caused great amusement/confusion/discussion over the years.

I was confused about 27/09, as I could have sworn that (in my days flying sims at Cranebank) it was 28/10.

Now I don'thave to worry about my failing memory!!

Thanks HD :ok:

(why did I never think about the mag-var change being responsible! - and well done to you and the reliant robin!!)