Vertical speed when descent

How many angels do you guys have when airplane is descending? Is over 2000 ft/min aggressive?

I usually use this formula:

V/S = Mach • 1000 • 3

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I normally target 1600-1800fpm. If your nose is more or less level with the horizon I would say it’s a good descent.

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2.200 feet/min then go calculating according to the horizon

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No, you are absolutely fine at -2000ft/min. You should rather base you descent on your speed and nose angle. As a passenger you won’t feel much at 5° for example. The thing you should actually worry about is the ears of pax but even that, it’s not that important hehe.

I once saw an instagram post of a 747 pilot going over 5000ft/min on climb over FL300.
The idea of limiting the VS is often due to misinformation or lack of knowlege (which was my case).

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Depends on a few factors. Here’s a few formulas.

Rod= Gs/60*(Ft/NM)
Ft/Nm is just your Alt divided by the distance to your destination
Gs is your ground speed

Say you are at 30,000ft 120NM from your destination going 300kts ground speed.

Rod= 300/60*(30,000/120)
Rod= 5(250)
Rod= 1,250FPM

If you have a VS you want to use instead of calculating one you can calculate Tod (Top of descent).
Tod= (Alt/Rod)(Gs/60)
Rod= the desired VS

Do remember to account for airport elevation when you are using these formulas. Just take your altitude MSL and subtract airport elevation.

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Yes but let’s just note that 5000 ft/min is absolutely rocket-shipping it.

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Yes it’s painful, On Ryanair flight they did fast descent and my ears were in pain for the next 2 days, so I like to just keep nice easy descent, unless I’m too high to make the destination

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I watched some airplanes on flightradar, usually, they started to descent at 800 ft/min, then gradually 1500 ft/min and then 2000 ft/min. Sometimes they reached 2500 ft/min. Numbers could change depending to distance, weather, geography and other conditions but gradually 800, 1500 and 2000 until 10.000 ft altitude are the most seening numbers i see on FR24.

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I aim for 1500-2000, but that’s my preference.

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It’s more the way around in IF.

The reason they decend that slow is probably because of STARs altitude roofs (sometimes they are very soon into the approach) or radar vectoring (the closer you are to the airport, the quicker you must change altitude).

But optimal descend would consist of having throttle idle the whole way. So you would reduce speed to 250 for example and make sure you don’t reach it until near FL100.

I don’t understand really why but you can litterally skyfall from + FL300 and yet not gain a lot of speed. So you can start at -3500ft/min and slowly bring that up (I am near -1800ft/min near FL150 most of the time).

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A steady descent is not fuel efficient, you shouldn’t do one.

Where are you referencing when you say that? If you’ve done proper flight planning fuel shouldn’t be an issue.

Because your engines are still running higher than idle, still consuming fuel.

I’d say it depends on your arrival planning. It can be difficult to properly plan for the best L/D. If you plan on using a STAR you need to be able to meet crossing restrictions.

It depends on when you start descent. For me, I start at ETE 18 min out and a V/S rate of -2000 works well.

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I’ve been using SkyVector or SimBrief now for ascent/descent profiles. Your descent depends if you’re descending over mountainous terrain or not. Most of my descents are in steps, starting gradually then getting steeper as I get closer - similar to most IRL descent profiles you can see on FlightAware.

As for speeds (IAS), most of the times I’m cruising at M0.78, so first step down to M0.75, then second step M0.67-M0.69, then 240 kts near FL110, and continuing to slow down to my Final IAS. VS is between 800-1600 depending on step, most of the times. This requires some quick, but easy math, as most steps are between 3k-6k feet for 2-4 minute fix points.

I wouldn’t use descent equations, because they rely on GS, which is always changing through your descent. You’ll more likely arrive too early, and have to descend in a holding pattern or you may have to call a missed approach.

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CaptJoe stated in his video on descent that VS is calculated by multiplying your Ground Speed by the angle of the glide slope you wish to descend at. So for a 3 degree glide slope you would have it as Groundspeed*3= VS on descent. For slowing your aircraft down it would be a glide slope of around 2.6 degrees so you would multiply your GS by 2.6 to find out your VA for slowing down.

With this formula you can get up to around -3000fpm on descent some times

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