Runway ID

"Hilton" wrote in message
nk.net...

SJC's runway 29 is 303.3 degrees.


ATW's runway 29 is 297.9 degrees.

On Sun, 16 Oct 2005 04:27:48 GMT, "Steven P. McNicoll"
wrote:

"Mike W." wrote in message
...

No, Bill has this right. If rounded correctly, 045 becomes 'runway 4' and
055 becomes 'runway 6'.

So why is it correct to round 045 down to 'runway 4' and 055 up to 'runway
6'?

Ah, because the REAL rounding rule, designed so that averages will not
become distorted high from rounding 1/2 up, is to round 1/2 to the
EVEN number.

I know of almost no teacher nor textbook that remembers this, much
less why it is so.

Morgans wrote:

"Mike W." wrote


No, Bill has this right. If rounded correctly, 045 becomes 'runway 4' and
055 becomes 'runway 6'.


I'm sure I read a reg quoted earlier in this thread, that you got to choose
going up or down, when it was --5.

You would choose the number to which the magnetic variation is taking
the runway. For example around the western US you would choose the
higher number as if you don't you'll have to renumber the runway that
much sooner.

Ah, because the REAL rounding rule, designed so that averages will not
become distorted high from rounding 1/2 up, is to round 1/2 to the
EVEN number.

I know of almost no teacher nor textbook that remembers this, much
less why it is so.

That's because it's not so.

The standard rounding rule is 5 goes up.

The catch is that you ONLY round from the digit after the one you're
rounding to. For example, .2447 rounds to .245 or to .24 or to .2
although a common error is to round (to the hundredths) as .25, because
the "rounded to the thousanths" version would end in a five. When
rounding, always round from the source, not an already adulterated version.

Jose
--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.

"GeorgeB" wrote in message
...

Ah, because the REAL rounding rule, designed so that averages will not
become distorted high from rounding 1/2 up, is to round 1/2 to the
EVEN number.


If these runways were at the same field, your method would have runway
designators that differ by twenty degrees for runways that have a difference
in azimuth of only ten degrees. I think I'd round both in the direction
that local magnetic variation was moving.

I have seen many runways get renumbered after enough years of slow
change in the mag heading. Daytona Beach is an example that I can
quickly remember. Runway 7 used to be runway 6 about 20 years ago.



On Sun, 16 Oct 2005 17:11:12 -0400, "Morgans"
wrote:


"Newps" wrote

You would choose the number to which the magnetic variation is taking
the runway. For example around the western US you would choose the
higher number as if you don't you'll have to renumber the runway that
much sooner.

What??? You don't rename a runway after it has been named.

The reg has been quoted. Show me where it says you have to take the
movement of magnetic variation into account.

"Newps" wrote

You would choose the number to which the magnetic variation is taking
the runway. For example around the western US you would choose the
higher number as if you don't you'll have to renumber the runway that
much sooner.

What??? You don't rename a runway after it has been named.

The reg has been quoted. Show me where it says you have to take the
movement of magnetic variation into account.
--
Jim in NC

"Morgans" wrote in message
...

What??? You don't rename a runway after it has been named.

The reg has been quoted. Show me where it says you have to take the
movement of magnetic variation into account.


"On a single runway, dual parallel runways and triple parallel runways, the
designation number is the whole number nearest one-tenth of the magnetic
azimuth when viewed from the direction of approach."

Morgans wrote:

"Newps" wrote


You would choose the number to which the magnetic variation is taking
the runway. For example around the western US you would choose the
higher number as if you don't you'll have to renumber the runway that
much sooner.


What??? You don't rename a runway after it has been named.

You most certainly do. Our parallel runways here at BIL were renumbered
from 27 R+L to 28 R+L several years ago. They did this at the same time
they rotated the VOR for the same reason. Another example is MSP. The
parallel runways there were 11/29 until a few years ago when they were
renumbered to 12/30

Crystal airport (MIC) in Minneapolis area went from runways 4/22 to
6/24 a few years ago. I don't know why so much change though.......