sulkair

Ok, I'm new to the Bus. But not so new that I shouldn't already know this. So if you scold me, I deserve it, that said I'd prefer you don't

Say you're descending via an RNAV arrival. managed speed, and managed descent. You do a little mental math and feel like you're cutting your next crossing restriction a bit close. So, you want to increase your rate a bit more. In my old airplane, if I was committed to speed mode, I would just tick up the speed knob 10 or 20 knots, keep the thrust levers at idle, and let the autopilot pitch over for speed thereby increasing the rate.

But... In the airbus, the only way I can ensure idle thrust is to pull open descent, right? But if I do this it will ignore my constraints (no good) In managed descent mode, if I pull/select speed and dial it up, how do I get it to pitch for speed vs spool up the engines? In other-words how do I enforce idle thrust without kicking off the auto-thrust, or pulling open descent?

Thanks

JRJ57

Pull open descent and selected speed and increase your speed. Also, select your crossing altitude so you don't bust through it. Once you caught up with your donut go back to managed descent and select your lowest altitude on the arrival.

sulkair

Thanks JRJ57. Seems silly to ask this on a message board when I could just talk about it with my CA - which I intend to do next trip, but I was relaxing today just staring at the ceiling thinking about the situation I was in on my last flight and wanted to get a quick answer. Thanks again.

Jetty

Yeah. Increase speed, then open descent and consider the speed brake if necessary.

KiloAlpha

Airbus considers within about 350' of a constraint to be close enough. Doesn't exactly inspire confidence.

emb145

I think it's actually 250' either side if selected altitude and +/- 10 on the speed.

KiloAlpha

Yep, you are right.

JoeyMeatballs

You could also make a PBD like a mile prior to the real constraint and put the alt constraint there. ( too much work I know)

OceanicPilot

Sometimes if given a crossing I will program the box with the assigned altitude restriction minus 500 feet or so. Works great.

Barneyrubble

Vertical Speed