Descent calculation fundamentals long hand

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

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

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All that formula…wooooowwwww blew my mind.

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

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

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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).

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Thanks for having explaint that piece of theory so well, @Brandon_Sandstrom :)

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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.

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

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Science class in infinite flight lmao

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

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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 :)

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a squared plus b squared equals c squared
Pythagorean Theorem
now I can tell my mom that IFC is educational :)

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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?

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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!

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

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