View Full Version : A320 CLB/DES question

18th Jan 2004, 06:22
Is it possible to engage a Managed climb or descend, with Selected speed instead of Managed?

I can't find any reference about this on my FCOM


18th Jan 2004, 08:37
As you are probably aware, by pulling the speed knob and setting a speed or entering a new speed into the CLB or DES pages of the MCDU, you can alter the climb or descent speed. With respect to your question however, my understanding is that the term "Managed" in the bus is mostly referring to the speed management. The aircraft will constantly adjust it's speed for maximum efficiency. Once the speed is overidden, then there is nothing for the airplane to manage.

Dream Land
18th Jan 2004, 10:55
The answer to your question is "yes", as long as you are in the NAV mode you can still select a managed vertical profile, by having a selected speed, it may have(the aircraft) a hard time complying with waypoint constraints when for instance in a descent profile you have strong tailwinds.

Dream Land:ok:

19th Jan 2004, 03:36
Yes,the moment you 'select' the speed different from the programme(it will always stay'aligned-track),the two arrows "top of descent/initiate descent' or the the level off index will appear on the track line.whereas in 'managed'it would climb/descent to the next alt constraint..:D

Spearing Britney
19th Jan 2004, 04:25
MAYDAY MAYDAY, to clarify your understanding the aircraft can still manage the thrust to descend to its profile at the particular speed you set, letting it have 'managed speed' just gives it more flexibiility for on the spot profile maintenance. Even in managed speed it intends to keep to the speed that is central to its allowed range, e.g if the economy descent speed is a typical 300 kts, it can (if it needs to) descend at 320, or slow to 280 depending on other factors, e.g. being held high/stronger than forecast wind etc.

Further to that modifying the speed in the CLB/DES pages is only really useful prior to departure/in the cruise respectively - more of a planning feature. Speed management in the climb/descent is done through the FCU(flight control unit - speed selection window).

hope that helps - and makes sense! ;)

19th Jan 2004, 07:08
Makes perfect sense. Thanks for the explanation.