The glide distance is what would be measured by the DME. However if you have the ground distance it’s should be this formula.

😂 I gave you the quick rule of thumbs in the tutorial. However also explained there inaccuracies.

All that formula…wooooowwwww blew my mind.

Thank you for taking the time to share this. It was a job in itself entering the data for us.

Bravo, what a well formatted and or executed tutorial in my own opinion!

So calculus? I think that’s it.

This is really good info @Brandon_Sandstrom - I honestly spent a good 30 minutes going thought the calculations to make sure I fully understood them.

Some may say - so what? Why do I need this? I am not doing this calculations en route. Indeed you are probably not. But understanding the theory is always important as part of becoming a better pilot (or better in anything really).

Do you have to use Trigonometry? I am learning it now only. ,':-( One Eyebrow Raised

Honestly no matter what your skill level in math, the equations are clearly written out and explained so just a bit of number sense and you should understand it. Make sure to read over multiples times to better understand.

Great tutorial ! Thanks a lot. By the way, in your formula i think you have written GS instead of GD.

Science class in infinite flight lmao

this is the exact type of stuff i do in science/maths

Love all the young ‘uns who think it’s Trig. It’s pretty simple work if you have a calculator. Either way, will be a learning curve for all those learning :)

a squared plus b squared equals c squared

Pythagorean Theorem

now I can tell my mom that IFC is educational :)

The other manner to calculate the TOD is apply the rule of 3. It is most easy and can check the descent for parts.

Example:

We are at FL 300 and we want to descend to 8000ft because is our IAF (initial approach fix) easy.

Current altitude= 30000

IAF =8000

Nm to descend=?

V/s = ?

30000-8000= 22000ft firt step

22000/1000= 22

22x3=66nm

Add 10 nm for variations of wind and v/s

TOD= 76 nm

To calculate the V/s

We take 250 kts our ground speed add a 0 will be 2500 and divided x 2

250+0=2500

2500/2=1250ft/min

V/s=1250ft/min

Obviously it is only for constant descent

You can fix any variation checking descent for leg

Example:

76nm of IAF We’ll be at Fl300

56nm of IAF We’ll be at Fl200 etc…

Keep on mind that any part of flight need a briefing before performing. Thanks

Wouldn’t it make more sense to use GS instead of IAS?

Divide your groundspeed by 2 and add a ‘0’ to give you your approximate rate of descent needed for a 3 degree descent.

Eg. 400Kts groundspeed = 400/2 = 200 add a 0 gives you 2000 fpm.

Worked for 30 plus years in the real world!

Rgr. Its the GS. I dont know why I wrote IAs. Sorry 😐

Rgr its the GS, i dont know why I wrote IAS. Sorry