How to get descent phase active without using approach phase

[Guest giln]

I have asked the question before of how to activate descent phase and i was told to activate approach phase. I don't like acctivating approach phase because it screws up my flight plan and i end up going to slow. I would like to know how to activate descent phase and have the computer manage my descent speed. How can i activate it???

[Guest A320_FO]

Hi,normally the DES phase is activated automatically when initiating the descent. However, this is only true if the FMGS is in CRZ mode. Assume you entered a cruizing level of FL340 during your cockpit preparation. Then, during flight, if you never reach FL340, the FMGS will remain in CLB mode. You can check the active mode by pushing opening the PERF page. At the top, you will see what the active FMGS mode.You can solve the problem, by opening the PROG page, and entering a new cruizing level (if you're flying at FL310, enter 310). Once in CRZ phase, you will be able to commence a managed descent simply by selecting a lower altitute at the FCU and pushing the knob.This is how Airbus states it (A320):Upon reaching the cruise flight level, the pilot should be sure that the FMA displays "ALT CRZ" or (---) in its second column, which ensures that the aircraft is at cruise flight level.The FMGS engages the "soft altitude" mode 2 minutes after the cruise flight level is captured and Mach stabilized. "Soft altitude" mode allows the aircraft to deviate

[Guest giln]

Thanks

[Guest giln]

I really don't understand how to get descent mode, everything you said is what i do but you did not really say how i can manually activte descent phase, all you did was tell me how to activate cruise, how do i activate descent phase?

[Guest almogo]

Well, the minute you start descending DES mode is activated. You need to descend manually and the display on the FMC will automatically turn to decent mode. Something that bothers me is that in order to keep a restrictions i.e ALT restriction i also have to do it manually by setting the ALT in the MCP. Example: i am at FL30 i set me ALT to 10000 and start to descend. If i have a restriction in the FMC for 15000 the plane will not level automatically unless of course i set the ALT on the MCP to 15000. So my question is what good are the restrictions if the plane won't follow them ? I was probably spoiled by the 737 who does this automatically but i do have to say the the TD point on the airbus is ore accurate comparing it to the 737 which almost never manages to descend without VNAV disconnecting.

[Guest A320_FO]

Hi, the issue you're describing, must be sim related. A real airbus, will not descend (climb) below (above) any alt constraints, when in managed descend (climb). It will however disregard all alt constraints when performing an open descend (climb)! This also means that you will have to fly in NAV mode. Using the HDG mode, will always automatically result in either open climb or V/S when you were previously descending (mode reversion).A good alternative to disregard all constraints (alt and speed) would be to use the expedite pushbutton.Airbus puts it like this:INTERACTION BETWEEN LATERAL MODES, VERTICAL MODES, AND MANAGED SPEED PROFILE When NAV mode is engaged :The FMGS guides the aircraft along the flight plan and considers the constraints attached to the F-PLN waypoints. As a result : Managed CLB and DES modes are available. The managed speed profile includes :V2 - SPD CSTR (if applicable) - SPD LIM - ECON CLB SPD/MACH - ECON CRZ MACH - ECON DES (AUTO SPD) - SPD/MACH - SPD CSTR - SPD LIM - HOLD SPD- VAPP/GS MINIt is valid for all vertical modes, except EXPEDITE (). When NAV mode is not engaged :The FMGS considers that the flight plan is not followed, and ignores all speed and altitude contraints linked to the flight plan waypoints. As a result : The managed vertical CLB and DES modes are not available. The managed SPD profile disregards the speed constraints and includes :V2 - SPD LIM - ECON CLB - ECON CRZ - ECON DES (AUTO SPD) - SPD LIM - VAPP/GS MIN target.As a consequence : When NAV mode disengages (manual or automatic) CLB mode, when engaged, reverts to OPEN CLB. DES mode, when engaged, reverts to V/S mode on current value. Speed and altitude constraints are disregarded (but speed limit is retained).Regards!