ATC would LIKE 1500 fpm but i believe (so I have been told) you only have to give them 500 fpm UNLESS they ask for more. BUT to say they reuire a HIGH rate of descent is not true. If they need 3000 fpm they are more likely to ask if you are able.

ATC would LIKE 1500 fpm but i believe (so I have been told) you only have to give them 500 fpm UNLESS they ask for more. BUT to say they reuire a HIGH rate of descent is not true. If they need 3000 fpm they are more likely to ask if you are able.

On a standard approach what is the CABIN Altitude Descent Rate?

On a standard approach what is the CABIN Altitude Descent Rate?

I am guessing by that time the cabin altitude has reached airport elevation.

On a standard approach what is the CABIN Altitude Descent Rate?

Hey man, in case you meant the actual cabin "V/S", that varies depending on the plane. Maximum V/S is 500 fpm, although for some it's 750. After landing the CPCs will continue to depressurize at 500 fpm if necessary. Once outside P is attained, outflow valve opens. Hope this helps.

Just like to thank you again Jack, I did a flight today that took me directly into the approach and ATC brought me in quite hot after holding me up at altitude for a while, using your tips in the last couple videos I was able to get on path with very minimal speed brake (50% for a very breif time to kill a little speed.). If it wasn't for your videos I would have used a lot of speedbrake.

ATC would LIKE 1500 fpm but i believe (so I have been told) you only have to give them 500 fpm UNLESS they ask for more. BUT to say they reuire a HIGH rate of descent is not true. If they need 3000 fpm they are more likely to ask if you are able.

Thanks for setting me right there Jack - not even sure where I read it lol - as they say 'don't ask, don't get' Cheers.John Ellison

I gave this a go today, and it worked perfectly - in fact it worked so well that I ended up being a little too low and had to fly S&L for a bit! Thanks very much for the tips. Adam Sutton

for all it's worth I never have to double tap or hold the brakes, I just tap it once, and hey presto!

How did you change registration tag under the clock?

There is no magic formula but it has to be noted that in general airplanes with highly efficient wings (such as the 737, A320, A330, actually all thin airfoiled wings) don't like to 'descend + decelerate', it's either 'descend' or 'decelerate' but never really combined. I used to fly an airplane which was able to do both but then again the name 'brick with wings' was a used nickname for it... ;) This entire debate is about 'energy management' btw. you need to consider your potential and kinetic energy level, being altitude(potential) and speed (kinetic) and combined they give you your 'energy level'... the trick is playing around with that... trading speed for altitude or opposite ...f.e. when hitting a turbulent layer of air... often we are climbing at an ECON speed around 310kias... but it never hurts to 'zoom up' through the turbulent layer by trading in your kinetic energy (310kias) for potential energy (higher altitude) (respecting minimum speeds of course, it should be noted that climbing at green dot speed gives you the best rate of climb but it will not be the most economical way of climbing as you will need a lot of time and power to regain your 'optimum cruise speed' after leveling off... so really it's a mix of a lot of factors but as Jack says, experience will bring most of the answers... try it out, if you miss it... so be it you learn from it. cheerz

Nice explanation. Think you can see all that you explain actually happening really well if you toggle on the VSD: white line shows how the plane tends to alter its trajectory during deceleration segments ... Great to watch! David

Hi jack, I have a few questions if I may, So whats the advantage of descending this way I am a little confused?? 2) Also with a tailwind component, this procedure is going to be a little tricky, then will you need spoilers? 3) -5000ft p/m is very high, is there any effect to the cabin pressurisation and will cause any discomfort in real life? 4) does the speed automatically tune down to [205knots] in lnav/vnav? All the best Alex

Alex, Jack is trying to point out that you have a large performance envelope that you can operate in - something many simmers forget about before turning to the speedbrake. If you ever end up high on profile and ATC don't mind you speeding up, this is a great thing to do as with a higher speed, you get to your destination quicker. You have already burnt the extra fuel maintaining altitude, so rather than waste this energy with drag devices, you may as well use it to your advantage. If you get really high on profile, using this technique with the speedbrakes can bring you back on profile very quickly. A tailwind will definitely affect your descent angle - you will need to judge the performance of the aircraft and decide whether or not you need speedbrakes. The rate of descent does not affect the pressurization system. The high rate of descent would be unnoticeable to passengers. The reduction of speed is a function of the VNAV - you have missed your ToD, where you are suppose to start reducing your energy (altitude), but since you have told the aircraft that you can't descend yet, it reduces the other type of energy instead (speed).

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Thanks David, everything I wanted :)

Can I ask once you descended steeply, interecepted and then went below the VNAV path at 320knts, how did you know to wait start to recapture the path when you were ~1400ft underneath it so you could kill your speed back to 256knts whilst comfortably settling back into the correct vnav descent path. Is there a simple formula saying that, for instance, every 10 knots of speed you need to kill whilst descending and rejoining the VNAV profile you will need to start your speed intervention 250 feet below the path? Or do you just do it empirically? Btw great vids, adds another dimension to descent planning rather than just slamming on the speed brakes.

I fly the real aircraft, and when using this method, the simple formula I use is that for every 10 knots faster than your desired on path speed, descend 200 feet below path before re-engaging vnav. Example: you increased speed in the dive to 320 knots to get to path, and your desired speed when on path is ~270 (ECON descent with cost index of around 20). You are 50 knots fast, so allow the aircraft to descend 1000' (200X50) below path before re-engaging VNAV (or exit SPD INT). The aircraft will pitch up to a 1000'/min descent at idle thrust and the speed should bleed off to very close to the desired ECON descent speed by the time you re-intercept path. Don't be too worried if it doesn't return to exactly the same speed - it will slowly. Hope that helps!