reply to post by Human_Alien
Yes, this has been happening periodically, systematically, for decades. I can remember when the Washington National Airport main (longest) runway was
18/36. NOW, it's 01/19. Same reason the TPA airport has to change the runway numbers.
Here's how it works......runway number is a cardinal heading, to the closest 10 (ten) degrees. And dropping the final zero.
Using the DCA airport, as example:
Runway 19's actual, precise magnetic heading, as of the date of that chart, is 186.3 degrees. Years ago, (I don't have copies, but the way it works)
the heading was LESS THAN 185.0 degrees...so it rounded down
to "180"...and the last zero is dropped, for the runway number. They may
let the runway numbering remain "as is" for some time, even if a survey reads the heading as "185.2"....but, eventually, they will update and revise
everything....(NOT just a matter or repainting the runway numbers, either. Pertinent aviation aeronautical charts are all revised, too).
The North Pole has been known to be slowly "creeping" for at least the last hundred years, since more and more accurate measurements have been made.
It is VERY gradual, and a matter of hundreds or tenths of degrees, when viewed from the scale of the overall size of the planet. It's simple
BTW, the TPA airport diagram, as of NOW (valid until 13 January, 2011):
As you can see, the "change" of the runway numbers is long overdue, there. The runway(s) headings are 186.5 degrees, for R/W 18L&R.....
Originally posted by getreadyalready
Great Find!! It is extremely uncommon, and almost unheard of to redesignate a runway! Especially a major runway, because it will also change every
approach specification for every airline in the world, and it has caused inconvenience to the neighborhood.
NO it isn't.
The "major" changes? Re-printing all the charts, as I pointed out. Aviation aeronautical charts are CONSTANTLY being revised. The biggest (and
only, AFAIK) private supplier of such charts, the Jeppesen Co., used to send a packet of revisions EVERY WEEK. Some years ago, about seven if I
remember, in order to cut down on mailing expenses, and paper costs (because, like any company, they can only raise their subscription fees so much)
they switched to every TWO weeks....at least, for the airline customers. Every time we go to work, there are revisions in our "V-files" (sort of
hanging folder that acts as a"mail-drop" for every pilot). For airlines, they are tailored by airplane fleet type, because the coverage varies so
(For instance, if you fly only the Boeing 737, you don't have the full Europe and Asia and Pacific coverage...North America, Central America and
Caribbean...IF on the B-777, then you get a lot more coverage, because of the many International destinations the equipment operates to.....)
edit on 5 January 2011 by weedwhacker because: (no reason given)