# When to start descent

what I do is multiply the first two digits (40) by 4 and descend at -1500fpm at 280kts. So 160 miles out. Sometimes I add like 10 miles to it to be safe. Works every time

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Same here. For long flight I usually cruise at ~20000FT.

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i cruised at 41k in a flight around socal yesterday ;)

I cruise wven lower than that. The maximum I ever cruise is at FL180.

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@Matt_McDonald just showed me this link of calculating decend, hope it helps

http://www.freedomair.us/DescentCalc/descentdistance.php

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i usually descend from 32,000ft and I start my descent 120nm out. VS of -2000 until I hit 10,000ft then I drop VS to -1500.If I was at 40,000 I would start at 140nm out same descent of 2,000ft.

I use a rule of thumb I saw a while back on the forum: altitude without the thousands (your example 40000 minus the 000) multiplied by three — so 40 x 3 (120). I would descend about 120 miles out. I usually add about 20ish miles to that to allow me some leveling out to lose speed. For example:

I would start descending at 1800 fpm roughly 145 miles out

Then level off at FL180 to contact approach. They would then vector me to the ILS.

If there is no approach online, I would lose some speed, then descend further. I usually descend to 3500 ft around where I think approach would clear me, then line myself up with the localizer. You just start getting a feel for it…

I will say the only time I’ve hit FL400 is in the SOFIA. Otherwise stay closer to FL200 to FL300. It makes controllers lives easier.

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Another rule I use for vertical speed (also found on this forum) is Ground speed x 5. Lets say your GS is 250 knots. Your VS would be 1250 fpm. This rule goes well along with the thumb rule by Rock77.

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Check this out! :)

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Yes James, I want a cabin full of puke.

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I realize. As of now I cruise usually at 10000 feet if its a long flight but nothing higher. I was just wondering for preparation of global flight

Awesome! Thank You

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Your GS is probably around 500…divide that by 2…gives you 250…so max Vs is -2500 for distance 40000feet…divide that by 1000 multiply by 3…so it’ll be 120nm away…add around 10nm so 130nm…that’s the simplest way possible…so in flight i just take the 1st 2 numbers 40×3=120+10=130…the ten basically accounts for maneuvers

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Decending from 40,000 feet with a decent speed of say 1500 kts, would take you roughly half an hour to get to normal pattern alritude… With the size of our regions that would be highly impracticle.

In real life an aircraft flying from Amsterdam to Brussels, would cruise at 15,000 feet…

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I cruise at 20000 usually for a trip that’s 100nm so i ascend at 4600fpm until i reach my height then i cruise at 280-290 and within 6-7 mins from the glidescope on gps/ils i descend at roughly 2400fpm until i get to 2 mins from the glidescope then i descend at 1400.

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Check this

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