Runway Numbers

[gertcoetzee]

It has been XY years since I have done any maths involving TAN etc. So please help. If I know the coordinates of the start and end of the runway, eg
27°49'49.01"E 33° 1'51.81"S
27°49'14.31"E 33° 2'31.45"S

how do I calculate the runway numbers?

I know it will be something like
Degrees = TAN (y1-y2/x1-x2) + 02

In Excel?

The idea is to look up the runway coordinates on google and then know the runway numbers....

[Bacchus]

Phone the locals.....much easier

[cobra]

Try the follow link

http://www.movable-type.co.uk/scripts/latlong.html

[cobra]

Distance : 1.519 km
Bearing :216°16′23″ from first co-ord to second

216deg + mag var 26W = 242 = RWY 06/24
______________________________________________

Distance

R = earth’s radius (mean radius = 6,371km)
Δlat = lat2− lat1
Δlong = long2− long1
a = sin²(Δlat/2) + cos(lat1).cos(lat2).sin²(Δlong/2)
c = 2.atan2(√a, √(1−a))
d = R.c

Bearing

Formula: θ = atan2(sin(Δlong).cos(lat2),
cos(lat1).sin(lat2) − sin(lat1).cos(lat2).cos(Δlong) )

what ever :D

[andrepieterse]

Remember to take variation into account as runway headings are magnetic.

[John Young]

Remember to take variation into account as runway headings are magnetic.

Hi Gert,

Yip, for our SA condx., add the west variation to true to get magnetic.

The main runway shown here is 06 / 24. You will see it as approx. 45° true.

For info, in Durbs magnetic variation is 23º W.

Variation decreases towards north up to the equator and increases towards south.

Regards
John ZU-CIB

[cobra]

Remember to take variation into account as runway headings are magnetic.

True, Thanks 216deg + mag var 26W = 242 = RWY 06/24

[GR8-DAD]

Dit was nou 'n maklike een....

[Biggles]

Just remember that magnetic declination varies with time. So while the magnetic bearing is 26o now it might have been different when the field was built. I belive they have renumbered runways in the past because the runway number was now far off the magnetic bearing.

So all in all call a local.

[John Young]

Just remember that magnetic declination varies with time. So while the magnetic bearing is 26o now it might have been different when the field was built. I belive they have renumbered runways in the past because the runway number was now far off the magnetic bearing.

Hi Biggles,

Depending on area, the magnetic variation will slowly and progressively change by 1° every 40 to 120 years.

Not enough to worry me in this lifetime.

This is normally shown at the bottom of the chart.

Regards
John ZU-CIB