# When should I start my Descent?

Hi, IFC! this is a question I have wanted to ask for some time now!
When should I start descending?!?!?

Yesterday I was going from KLAX to CYYZ and I thought I should start descending! I had AP on so all I had to do is lower the altitude number! I could see that the altitude was going down slowly (which I thought was normal!) and by the time I got to the airport I was still at 25,000ft!!! So I had no choice but to dive! I do not want to dive because this make my flight much less realistic and there is a BIG! chance of getting VIOLATIONS!!!
I have tried disengaging AP and then lowering the nose but the plane does wobble a lot!

Could someone tell me when I should start descending?
Thank you
Happy landings ✈️
@captainmalik

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This should help

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Adding on to what was said by @SterlingArcher, You can change the VS. It’s how fast You go down. Usually it’s automatically set to 250 feet per minute, You can change that though. Don’t go 5000fpm, that’s really dangerous.

I disagree. Realistically, if such a situation was in place, You would circle the airport descending at a normal rate.

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Oh, ok I had no idea what VS was! Thanks 😂😂🤣

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Thanks for helping !!!

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A good idea also is to use Simbrief, which calculates TOD - I think - or to use STARs, which will at least make you do a dive away from the airport ; )

I do mine by taking my cruise for example 37,000. Then i times 37 times 3 and get 111 and you can add 10 or 15 to that to be safe. so lets say 121 is TOD. and you find your vs by taking your groundspeed and adding a zero to the end and divide that by 2. so lets say 520 i my ground speed and add a zero then its 5200 divide by 2 is 2600 so your TOD is 121 and your vs is -2600. pretty simple right? so hope yo understand and if you have a question pm me :)

it does stars and sids and TOD by i don’t trust it bc the descend rates can be crazy sometimes

Their is an App called VirtualHub I have, it has charts and checklists and a decent calculator, it does tend to add a few extra Nauticle Miles though, so be careful!!

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@Chris_S has a very good site that works with SimBrief and also has a summary of various legs of your trip incl vertical spd, altitude, airspeed etc.

fpltoif.com(By Chris_S)It supports flightaware and SimBrief.
simbrief.com

And you know the best thing? THEY ARE FREE.

Edit: VirtualHub is also a very trusted app for these kinds of situations.

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Interesting, I’ve never had an issue with Simbrief’s TOD calculations. I’ve always needed to tweak its route generator because I think Infinite Flight has an older AIRAC than 1704, which is Simbrief’s default AIRAC. I don’t think Infinite Flight has RNAV points either, so STARs and SIDs can be tricky. Please correct me if I’m wrong.

Ok will try the app!!

i believe that the AIRAC is older in IF. However sometimes for me descend by -14000 lol. So i contacted my buddy who fly’s in the air force in the KC-135 and he gave me that formula and it works every time

Partly correct if I understand you correctly though more waypoints(mostly fixes) are being added by the Airport Editors.

Personally, I use formulas to check TODs for Simbrief. Use them if you prefer them 👌

Great! To get to the decent calculator hit the three lines in the left corner and hit the button labeled TOD

RNAV waypoints are generally newer than fixes, so I would assume that it would take time to add them.

If only Infinite Flight had Navigraph connectivity lol. Maybe that’s an idea for the add on devs.

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(Cruising altitude - (final approach altitude + altitude of airport)) / vertical speed.

(36000 - (3000 + 83)) / 1800 = 18,29.
When you start 18 minutes before arrival with a VS of 1800 you see that you have a margin of +/- 1,5 minute.

Please notice that you must set 3000 ALT!

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Here is how I do it and it maybe rough.
7,500-15,000 ft 30-50 nm
15,000-25,000 ft 50-80 nm
25,000-35,000 ft 80-120 nm
35,000-40,000 ft 120-150 nm
VS ranges from initial descent 800 fpm to descent no more than 2,200 fpm.
That is just me though lol

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This is a really good tutorial by @Swiss on a smooth landing, including descent calculations.

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