Vertical speed bottom of descent arrow (blue hockey stick) to how ever many miles (1 mile for every 10 kts airspeed) prior to crossing restriction with speed. Adjust roughly 10% +\- for HW/TW. If you forgot to descend and you have to VS down > 5000 FPM, Arrest excessive speed with, wait for it, "speed brake". Tell a-hole who says to use selected airspeed because "that's how we do it" to ****. Not complicated.

 

Turn down the indicated IAS to minimum clean and use the VS you need. It will got to idle and you can control the rate of descend perfectly. As soon as you reached the constraint, you can fly your advised speed again.
In my experience the A320 is very pitch sensitive in open descend, the pitch attitude changes all the time. For passenger comfort VS is in my opinion the better choice.

 

Yeah, I'm personally a fan of v/s myself, however I've gotten a lot of nervous CA's sharing their thoughts that it's the fastest way to get in trouble in this airplane. You know my job is also to keep Ol' Bob over there happy I sure do appreciate all the responses - thanks guys!

 

When programming the decent winds I ALWAYS lie to the FMS. If descending with a tail wind I triple it, if descending with a head wind I eliminate it. I go selected speed to maintain IAS. Works like a charm. And always force it to recalculate by re-entering the altitude at the next fix or going direct to it. Remember the FMS calculates the decent backwards from the runway to your PPOS. It's also a geometric path i.e. point to point, not constant rate.

 

Why are all you people fighting the superior Airbus logic??? Don't you know the airbus is smarter than all of you? It knows better, and you are just a distraction to how it wants to fly anyway. You are only one of about 30 inputs and it will decide what is best for you. Release yourself to Fifi and she will take care of you. Or not. It all depends on whether she has recalculated properly, or got hung up on some simple math. It's French math.

In all seriousness, like someone said, it will honor a constraint within 250 feet. The FAA has certified this airplane to fly in our airspace like this, so they have deemed the amount acceptable. In managed mode, the airplane flies a vertical line from point to point, and selecting increased speed will not alter that line, it will just make you go faster along it. If you are concerned about overshooting a constraint too high, you can always dial the constraint altitude into the FCU and pull for OPEN DESCENT. When it levels off and crosses the constraint, dial in the next constraint altitude, and so on. It's a little more work, but it's available if you're concerned you won't make the restriction. And don't be afraid to use the speed brakes (only in open descent). When I first got on the bus, the Captains' attitudes were "speed brakes are for sissies." That attitude has changed, and I use them frequently at certain airports who like to slam dunk you *cough* Detroit *cough*. And remember to enjoy flying the bus. Just don't let it make you lazy.

 

Great posts everyone! Thank you! You mention use the brakes only in OPEN DESCENT. At first I thought - of course - because you're flying that "vertical line" and deploying the speed brakes would only force her/it to add power to maintain it. But... When the airplane asks for MORE DRAG, it's ok right, because it would already be at IDLE and needs more IDLE. Yes, No?

 

Occasionally you will see Fifi ask for more drag. You give it to her and then she adds more thrust.
Last flight, one MCDU asked for more drag and the other MCDU did not.

 

Here's a good write-up covering the nuts & bolts:

http://www.smartcockpit.com/download...nitoring_1.pdf

 

Yes, when it asks for more drag, fifi has decided that she cannot descend fast enough to catch up to the (vertical) line and won't make a constraint. She's asking for your help. Occasionally in selected speed, when you put the speed brakes out it will slow down more than it wants while trying to keep the pitch down movement slow and smooth for the pax and it will run the thrust up to catch back up on the speed while pitching down. It's the smoothness programming (load factor demand) working against itself. It is programmed to consider speed first in most regimes as long as you don't override it (Vert spd). Now if it is adding thrust in an established descent, I have no answer for that.

 

Other than in OPEN DESCENT mode, in descent A-320 keeps thrust idle almost always when selected speed triangle (doesn't matter blue or magenta) is BELOW IAS.
In other words: you can be in V/S or Managed Descent, but if the aircraft is moving faster than desired (selected/managed) speed - it goes to IDLE. That simple.
And when she says THRUST IDLE you can always use your speed brakes, don't need to pull ALT knob for that. Just monitor RPM to retract the brakes as needed.