How many miles from the airport that jet is going to land, starts it decent from an altitude of 37000 ft?

Question

How many miles from the airport that jet is going to land, starts it decent from an altitude of 37000 ft?

Answer 1

Just for ballpark, use 3 miles per 1000 feet of altitude needed to lose. When you get to 10,000 ft, you'll have to slow to 250 kts. Add about a mile for every 10 kts of airspeed to lose.

So if your airport is at sea level, you'll start about 111 miles out. If you're at 300 kts in the descent, tack on another 5 miles to that. If you've got a tremendous tailwind, you might be hard pressed to make any crossing restrictions that are thrown your way on the way down. So start a few miles earlier and keep track of your vertical progress by cross checking your DME to make sure that you're on your intended profile.

Answer 2

131nm

Answer 3

Please have a look at a table I recently created to guide me down the shortest route possible from my cruise altitude to the runway (assuming no traffic or vectors from ATC). For 37,000ft...I would say 116.10nm...based on what I said above.

Answer 4

assume a decent of 2000 feet per minute, take your altitiude, subtract the landing airports altitude - divide by by 2000, that is the number of minutes you need to get down, multiple that by the airspeed (covert to miles per minute) and that is how far out you need to start.

ex

37000 ft -to 2000 - decend 35000 ft at 300 knts, 2000 fpm, so it will take 17.5 minutes - you will travel 82.5 miles (300 mph is 5 miles/minute) so 80 miles out for that decent rate.

Answer 5

The "times three rule" is a good rule of thumb. (Altitude loss in thousands of feet times 3 = distance.) It is roughly based on 300 feet per nautical mile (all distances are nautical)  or roughly a three degree descent profile. However, in reality, ATC will do its own thing. As for the previous post, 17.5 X 5 = 87.5, not 82.5 and it's "descent" not "decent". "Decent" is "He was a decent man" or "That's indecent!"

You don't have to be a spelling wiz to be a pilot, but correctly spelling the words used in the trade is not a bad thing.