atpl question!
Thread Starter
Joined: Dec 2005
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From: norway
atpl question!
Hei, could somebody please help me with a atpl question on navigation? How you do you calcuate it?
Any help would be greatly appreciated!
The great circle distance between position A (59°34.1'N008°08.4'E) and B
(30°25.9'N 171°51.6'W) is:
A:10800nm
B:5400nm
C:10800km
D:2700nm
Any help would be greatly appreciated!
The great circle distance between position A (59°34.1'N008°08.4'E) and B
(30°25.9'N 171°51.6'W) is:
A:10800nm
B:5400nm
C:10800km
D:2700nm
Joined: Feb 2009
Posts: 49
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From: above the clouds
If you look at the longitudes of A and B, you can see that the longitude of B is the anti-meridian of that of A. Therefore, the great circle track between them will be accross the nearest pole. You therefore need to work out the distance from A to the pole, and then from the Pole to B.
We know 1 degree of latitude = 60nm
A > pole = 90-59°34.1' = 30°25.9' = 1826nm
pole > B = 90-30°25.9' = 59°34.1' = 3574nm
Therefore, total distance = 5400nm (B)
C89
We know 1 degree of latitude = 60nm
A > pole = 90-59°34.1' = 30°25.9' = 1826nm
pole > B = 90-30°25.9' = 59°34.1' = 3574nm
Therefore, total distance = 5400nm (B)
C89
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What he said but using Calculate distance and bearing between two Latitude/Longitude points using Haversine formula in JavaScript and CalculateMe.com - Convert Kilometers to Nautical Miles
Here to help
Here to help
Joined: Nov 2007
Posts: 414
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From: Hoylake
Its been a while! but here we go,
Draw the picture, a polar stereographic picture of the northern hemisphere, looking at your 2 points A and B you are going straight over the top.
1 deg of lat = 60 nm
So your calculation is simply a total change in Latitude x 60
Total change in latitude is
90-59°34.1' = 30°25.9'
90-30°25.9' = 59°34.1'
add them together and x by 60 = 90x60=5400nm
Draw the picture, a polar stereographic picture of the northern hemisphere, looking at your 2 points A and B you are going straight over the top.
1 deg of lat = 60 nm
So your calculation is simply a total change in Latitude x 60
Total change in latitude is
90-59°34.1' = 30°25.9'
90-30°25.9' = 59°34.1'
add them together and x by 60 = 90x60=5400nm
Last edited by Nearly There; 15th July 2009 at 21:31. Reason: took to long to find degrees on the keyboard, the guys above beat me to it!
Supercharged PPRuNer
Joined: Nov 2000
Aviation Qualifications: ATPL
Posts: 1,188
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From: Doon the watter, a million miles from the sandpit.
And remember that once you've passed the exam, you'll never, ever, ever have to do that sort of calculation again.
Possibly the most useless of all ATPL subjects - and that's up against some pretty stiff competition.
Possibly the most useless of all ATPL subjects - and that's up against some pretty stiff competition.
Joined: Nov 2000
Posts: 4,330
Likes: 74
From: White Waltham, Prestwick & Calgary
A small tip is to add up the longitudes - if they make 180 you know you have to go over the Pole. I'm surprised they haven't got 5400 km in there somewhere.
SXTY - I wasn't exactly going over the Pole in a helicopter but I was using such calculations all the time in N Alberta.
phil
SXTY - I wasn't exactly going over the Pole in a helicopter but I was using such calculations all the time in N Alberta.
phil
Joined: Aug 2023
Posts: 21
Likes: 0
From: VANDA
Resurrecting an old question
Hi all, apologies for resurrecting an old question
The solution from Nearly There above was a great help.
BTW, what if we were NOT going straight over the top? Let's say 45°N 20°W to 30°N 20° E?
What would be the simplest way of calculating this without the complex Haversine...
Many thanks!
The solution from Nearly There above was a great help.
BTW, what if we were NOT going straight over the top? Let's say 45°N 20°W to 30°N 20° E?
What would be the simplest way of calculating this without the complex Haversine...
Many thanks!
