STEP CLIMB

[JESUS_LOSPI 0]

Hi guys,

 

Sometimes I need to perform a step climb because of the winds or the diferent levels between airways. ¿Which is the proper procedure?¿Where do you set the new cruise altitude?¿Will the MCDU calculate a new T/D virtual point?

 

Thanks in advance

[datguytho 38]

When you climb from your cruise altitude to a different level the FMS will automatically edit the crz altitude you entered before flight. In the moment you climb, there is a text like "NEW CRZ ALT" or similar displayed in the bottom of the MCDU which tells you that the crz altitude has been updated. 

And yes, the T/D is getting updated frequently based on the altitude and other performance factors.

[Pablo__sk8 29]

Well, one way is programming the step climb in the MCDU FPL page where at the left you can see the VNAV altitude corresponding to every WPT, if I were you, I would put the altitude you want to be at every waypoint during cruise. For example: If you have to cruise at FL340 until MEROS, where you have to be at FL370, put FL340 at all the cruise WPT's that are before MEROS and then put FL370 from MEROS and the following WPT's. At the MCP you would have to select the highest step climb (let's say FL370) and press the button, NOT PULL, so the plane follows the programmed VNAV route.

[JESUS_LOSPI 0]

OK. ¿same procedure for a descent?

[Pablo__sk8 29]

51 minutes ago, JESUS_LOSPI said:

OK. ¿same procedure for a descent?

Yes, but the descent altitudes are normally automatically calculated with the route, so you only have to put the altitude (for example 5000ft) on the MCP and push the altitude knob.

Then the aircraft will automatically manage the descent rate and the speed (you will see like a pink limiter on the PFD for the speed and at the left of the PFD altitude indicator you will start to see a little pink dot that will start to go to the middle (like a glideslope but a bit different, for the descent) and the aircraft will descent at the correct rate and will respect every restriction (altitude & speed). All this is preprogramated when you enter the LDG RWY, the STAR, TOD,... and all the info is calculated automatically. The only thing you will have to do then is prepare the APP PHASE in the MCDU, and press it during the approach. You can also manage the speed manually because as soon as you push the "CONFIRM APPROACH PHASE" button the aircraft will reduce to the precalculated minimums speed, so I prefer to reduce the speed "step by step" and not go from 250kts to 117kts directly. I start to reduce to minimums on the ILS.

[datguytho 38]

Just wanna add that all of this of course depends on where you are flying. Normally pilots will not edit the altitude at waypoints, only during descend, when the ATC tells you to be at a specified altitude at some waypoint. And of course step climbs do not need to happen on a specified waypoint etc.

Also, you want the Airbus to follow a flight profile that goes along with the cost index and the aircraft performance. Therefore a real pilot would never type in the stepclimbs on the flight plan page as this automatically adjusts your FL as well. If you are at FL340 and wanna climb further to FL370 you would not go with a managed climb (which is activated by pushing the altitude knob down) but you instead adjust the V/S. If you activated managed climb during climb phase this would result in an immediate nose-up pitch. Of course airlines dont want that to happen... 

 

So as you asked for the correct procedure to do a stepclimb, this is how it works:

 

1. On the INIT page in the MCDU, use your initial flight level, aka the the flight level you want to use in first place.

2. Climb to the initial flight level by using managed or open climb mode. Monitor the PROG page on the MCDU which tells you which flight level is recommended for your aircraft right now.

3. If you are ready for further climbing, change the altitude and pull the V/S button, controlling the vertical climb speed (1000 fpm would be a typical value, but thats part of the company procedures for every airline) do NOT just push or pull the altitude button.

4. The MCDU will automatically change the Flight level to the altitude you set up. 

Thats basically how you perform a stepclimb