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# Maths problem for those more intelligent than I

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# Maths problem for those more intelligent than I

17th May 2013, 19:57

Join Date: May 2002
Location: London
Posts: 30
Maths problem for those more intelligent than I

Can someone help with this please?

I have a runway in China for which I need to calculate the threshold coordinates as the AIP does not give them.

RWY 15(154) 33(334)
ARP Centre of rwy N3159120 E11658300
Rwy length 3400m (11154ft)

Many thanks
Panda
18th May 2013, 01:30
Vercingetorix
Guest

Posts: n/a
PANDAMATENGA
You need a PANS - OPS qualified guy for that. There are on or two to be found but they are a rare breed in these (not) so august forums

Last edited by Vercingetorix; 18th May 2013 at 01:31.
18th May 2013, 01:56

Join Date: May 2002
Location: London
Posts: 30
Thanks Vercingetorix
I see there have been many views but no comments so perhaps I am not as stupid as I thought!!
I just assumed there would be some formula involving Sines/Cosines or perhaps Quantum Physics.Anyway I have sent a pm to one of the RAF Navs in the hope that he can help.

Cheers
PANDA
18th May 2013, 04:33

Join Date: Jan 2001
Location: North Queensland, Australia
Posts: 2,869
18th May 2013, 05:00

Join Date: Jul 2012
Location: Cluj-Napoca, RO
Age: 40
Posts: 23
If it's just a matter of spherical trig then:

Lat1 = asin[sin(Lat0)*cos(D) + cos(Lat0)*sin(D)*cos(A0)]
Lon1 = Lon0 + atan2(sin(D)*sin(A0),cos(D)*cos(Lat0) - cos(A0)*sin(D)*sin(Lat0))

Or about .. Rwy33 N3158304 E11658584 and Rwy15 N3200095 E11658015

18th May 2013, 05:05
Ecce Homo! Loquitur...

Join Date: Jul 2000
Location: Peripatetic
Posts: 10,746
Only works if it is 'a true 15/33 and the magnetic variation has not changed since the last survey; and are you sure of the Geodetic Datum used for the runway centre point?
18th May 2013, 18:55

Join Date: May 2002
Location: London
Posts: 30
Thank you Radu and ORAC the problem is now resolved.
Having done a revalidation on the database at work the system has done a recalculation and all is well.

Bregds
Panda
18th May 2013, 21:10

Join Date: May 2001
Location: Newcastle/UK
Posts: 1,477
Do trident warheads need that sort of precision? I would have though anywhere on the runway would do the trick.
22nd May 2013, 11:10

Join Date: Apr 2010
Posts: 92
People who struggle with maths problems might fare better after a course of gentle electric shocks to the brain, scientists have claimed.
Mild electric shocks to brain may help students solve maths problems | Science | The Guardian
22nd May 2013, 17:16

Join Date: Apr 2008
Location: Garden of England
Age: 81
Posts: 165
That's all very well (the "mild" shocks probably fully woke up the dozy ones amongst them), but which group got the most maths questions correct? Speed increases of 27% are neither here nor there, what matters most in mathematics is ACCURACY!

There are quite a few structures in various parts of the world that I used mathematics to design, without once having my brain electrically shocked to finish 27% quicker. To the best of my knowledge, they are all still standing, carrying traffic, being lived in, and performing as required with adequate factors of safety. Remember the fable of the tortoise and the hare ...
22nd May 2013, 17:31

Join Date: Apr 2007
Location: egsh
Posts: 415
Maths problem for those more intelligent than I

Than me

Repeat after me, boy, than me . Fundamental grammar.
22nd May 2013, 17:52

Join Date: Jan 2008
Location: Boston
Posts: 31
Hey, Grammar Nazi

"Maths problem for those more intelligent than I (am)".
22nd May 2013, 18:22

Join Date: Apr 2007
Location: egsh
Posts: 415
Had "am" been there, you would have been correct. As it is, you are wrong.
22nd May 2013, 18:26

Join Date: May 2002
Location: London
Posts: 30
Wings Folded
Not that I really give a toss but I suspect both are correct.Perhaps it depends where one learnt one's grammar.
Maybe you have spent a lot of time in "me love you longtime" land!!
22nd May 2013, 18:43

Join Date: Apr 2010
Posts: 92
There are quite a few structures in various parts of the world that I used mathematics to design, without once having my brain electrically shocked to finish 27% quicker.
yeah, 603DX, but if you had been shocked, you might have finished 54% faster!

And a story to grammar nazis - by my old professor from the 80s: A young boy is standing in front of the mirror and saying: "It's me, it's me, it's me!" - and Granny corrects him: "It's 'I', honey." And the boy looks in the mirror in doubt and says: "Well, it may be I, but it looks very much like me!"
22nd May 2013, 19:14

Join Date: Oct 2006
Location: UK
Posts: 4,980
Having done a revalidation on the database
Just as well, otherwise you would have carried out an approach on to some rice paddies.
23rd May 2013, 11:09

Join Date: Feb 2010
Location: Slovakia
Age: 62
Posts: 162
This is like a “Who dun it”

“ARP Centre of runway N3159120 E11658300”

That is UTM ZONE 50
Starting Meridian E114°
Central Meridian E117°
Ending Meridian E120°

Ellipsoid – WGS-84
Semi Major Axis [a] 6378137 Eccentricity [e] 0.0818191908426215
Scaling Factor 0.9996
Projection Transverse Mercator

“RWY 15(154) 33(334)”

It is presumed that the runway bearings are magnetic.

Theoretical Magnetic Variation at ARP

ARP Position
Latitude 31°59'12.0000"N
Longitude 116°58'30.0000"E
Parameters
Magnetic Variation Model WMM 2010
Magnetic Variation Date 23 May 2013
Result
Magnetic Variation 4.9284°W

Magnetic variation taken as 4.9°West

Runway True bearings 149.1 / 329.1

“Rwy length 3400m (11154ft)“

Determine the Position of THRESHOLD runway 33

ARP
Latitude 31°59'12.0"N
Longitude 116°58'30.0"E
Magnetic Variation 4.9°W
Forward True Bearing 149.1 °
Forward Magnetic Bearing 154 °
Distance between positions 1700 m
Calculation: Ellipsoidal
Result Threshold runway 33
Latitude 31°58'24.6"N
Longitude 116°59'03.2"E
Reverse True Bearing 329.1°
Reverse Magnetic Bearing 334.0°

Determine the Position of THRESHOLD runway 15

ARP
Latitude 31°59'12.0000"N
Longitude 116°58'30.0000"E
Magnetic Variation 4.9°W
Parameters
Forward True Bearing 329.1 °
Forward Magnetic Bearing 334 °
Distance between positions 1700 m
Calculation Type Ellipsoid
Result Threshold runway 15
Latitude 31°59'59.4"N
Longitude 116°57'56.8"E
Reverse True Bearing 149.1°
Reverse Magnetic Bearing 154.0°

On Google Earth it looks like the multi-runway airport is not built yet.
The ARP looks to be centred between the two parallel runways.

Panda, did you finally get something similar?

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