ATPL General Navigation - Class 2: Latitude and Longitude. 

Niceeeeeeee! Keep up the hard work!

congratulations, i wish i will get the same!

Yes absolutely. I was trying to show it in as basic a way as possible but if you can skip right through to that part then it will save you a bit of time during the exam.

Kindly explain dep= Ch.long x 60

@@musaraza282 so the formula for departure is: Departure = change of longitude (in minutes) x cosine latitude. So the formula translates to: 280nm(departure)= change of longitude x 0.707(the cosine of 45 degree latitude) So then rearrange the formula to find the change in longitude in minutes: Change of long= 280/0.707 Change of long=396 minutes There are 60 minutes in 1 degree. So divide 396 by 60 to find degrees 396/60= 6.6 degrees. Multiply the .6 degrees to find the minutes 0.6 x 60 = 36 minutes So 6 degree 36 minutes change in longitude But, their formula: depature= change in longitude x 60 x cosine of latitude basically is accounting for changing the change of longitude from degrees to minutes, that is all it is. (degree change in longitude x 60 = change in longitude in minutes) I hope this helped. I struggled to get my head around the maths at first, but it all clicks into place

Best of luck!

So the distance that covers 1degree of longitude will change depending on how close we are to the equator. This is because all of the longitude lines squeeze together at the poles. At the equator we get 1 degree of longitude = 60nm whereas if we were right at the north pole we could run around all the degrees of longitude in a few meters easily, like spinning round a broom handle. This means that the distance covered by 1 degree of longitude is proportional to how close to the equator we are in terms of our latitude. Really close to the equator (0 degrees lat) = almost 60nm: really close to the pole (90 degrees lat) = almost 0nm. So we use the cosine function to find out the level of this proportional change. In the example of N45 the 1 degree change here is only 70% of the size of the change at the equator. So 280nm is 70% and when we scale it up to the equator (100%) we get 400nm, we can then use that distance and our knowledge that at the equator 1 degree = 60nm to find out the change in degrees longitude which is 6.6 degrees.

400 / 60 = 6.6. Which is 6 degrees and 0.6 of a degree. 60 minutes per degree. Each 0.1 = 6 minutes Therefore 0.6 = 36 minutes.

It's not really going to make that much difference in all honesty. If the answers in the exam are different by 0.1 then that's not testing your knowledge of the subject just your ability to round a number.

We're converting to a base 60 counting system. So each 0.1 in regular the decimal system equates to 6 minutes in the base 60 system.

You need to take it down to the equator using 100% because that is the only latitude line where 1minute = 1nm.

You can calculate the change "directly" (by not going down to 100%) by using: DEP = ch.long x 60 x cos (lat). 1) 60 x cos(45) = 42,42640687 2) 280 NM ÷ 42,42640687 = 6°35'58.79" We're moving WEST from a position in EAST, subtract W from E = 45°15' E - 6°35'58.79" W = 38°39' E

​@@roynorbawsome man thanks I didn't know I could do that ❤ u a life saver too

It's hard to tell without seeing mate, have a google, make sure you are pressing the button after every number. Possibly ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-n7r2TROlbiQ.html

@@atplclass Thank you mate! Subscribed to your channel.

So the distance that covers 1degree of longitude will change depending on how close we are to the equator. This is because all of the longitude lines squeeze together at the poles. At the equator we get 1 degree of longitude = 60nm whereas if we were right at the north pole we could run around all the degrees of longitude in a few meters easily, like spinning round a broom handle. This means that the distance covered by 1 degree of longitude is proportional to how close to the equator we are in terms of our latitude. Really close to the equator (0 degrees lat) = almost 60nm: really close to the pole (90 degrees lat) = almost 0nm. So we use the cosine function to find out the level of this proportional change. In the example of N45 the 1 degree change here is only 70% of the size of the change at the equator. So 280nm is 70% and when we scale it up to the equator (100%) we get 400nm, we can then use that distance and our knowledge that at the equator 1 degree = 60nm to find out the change in degrees longitude which is 6.6 degrees.

Using the calculator just 280 nm /70 = 400@@atplclass

the equator (100%) we get 400nm. so 280 is only the 70% of the equator @@jasonalexander7178 he explained it well.