Step Climbs During Cruise

[WernerAir]

Hi there,

I wanted to ask whether the FMS-assisted step climb functionality is fully implemented in the MSFS version. Because I have not been able to get it to work.

Several times now I have set up the step climb as described in this video: https://www.youtube.com/watch?v=TQgv0VZAKGM&list=PLzeFYXw62MgZTxwGc-ogOuIlx8o5HdsK3&index=2 - of course the video refers to the X-Plane version of the A310, but behavior of the FMC is as described, and the S/C point is also shown on the ND. When approaching the S/C point, the FMA "P.Climb" even starts to blink in blue under "P.Alt". So everything as expected so far. However, once the aircraft reaches the S/C point, instead of engaging P.Climb it just remains in P.Alt at the current altitude. The aircraft only starts climbing after pulling the altitude selection knob manually. Is this a bug, or am I doing something wrong?

[Deleted Account]

Heya!

I just tried this myself and the plane auto climbed as expected.

How quick did you pull the knob? Maybe the plane was about to begin the climb when you pulled it?

[Deleted Account]

Actually I just managed to reproduce it. Was your step climb point in front of a sharp turn by chance?

[WernerAir]

The LNAV path has been pretty straight in all instances I have tried so far.

I am going to start a flight just now, and try to document it more precisely.

 

[WernerAir]

OK, here is the first test of the day: I am flying from LMML to EGKK - attached you will find the SimBrief flight plan I am using.

The flight plan calls for an initial climb to FL300, and then a first step climb to FL360 soon after at waypoint ADEXI. Later, a second step climb to FL380 is foreseen at PIGOS.

I have made three screen videos, which you will find here: https://c.1und1.de/@520185075732578887/EAJQA_mMQUCq9bNjMOWpMQ

• The first video shows me setting up the first step climb shortly after reaching the initial cruise alt of FL300. Here, everything behaves as expected.
• The second video shows the moment when the aircraft reaches ADEXI. As you can see, the aircraft just doesn't climb, and the step climb somehow remains pending in the FMS. I wouldn't call the turn at ADEXI a sharp one.
• The third video shows another curiosity, which is me trying to set up a second step climb. This should not be possible according to the video cited above. Nevertheless, the FMC let's me insert the step climb, but then behaves strangely with the (S/C) appearing and disappearing at intervals.

The videos do not require a password to access, and they will be online for a month from now. I hope this helps understanding the problem - and maybe finding the cause.

LMMLEGKK01.fpl

[FelixM]

HI,

I just tested it myself and can confirm that it is not working as shown in the Video. (Running on Xbox X)

1. Flying leveled at CRZ Alt FL340

2. Insert Step Climb for the next Waypoint to FL370 (FMS is now updated to FL370)

3. Changing Altitude knob to FL 370

4. Getting P.CLB flashing Blue in the FMA shortly before reaching the waypoint

4. Crossing the Waypoint - nothing happens. P.CLB flashing in blue just vanished.

Comment: There was no turn followed after waypoint , pretty much a straight line.

 

Best regards,

Felix

 

[Deleted Account]

It definetly does auto climb. In fact I managed two make it autoclimb twice in a flight; this is normally possible by the way, you just cant plan multiple steps from the get go. So you can set your initial CRZ to 300, configure the step to 340 and once you climbed to 340, you can configure the climb to 360 etc.

Here is a video of me showing the autoclimbs: https://streamable.com/a8h7vz (Video will expire in 1 day unfortunately)

 

[FelixM]

This is really strange. I will make a video as well after Christmas. I'm doing it exactly the same way and the plane doesn't climb. Maybe you can spot something I have done wrong. But I mean there is actually not much you can do wrong hmm....

[FelixM]

@gumbygerJust spot something. Is it possible that in your case your new step climb altitude was lower that the optimized FL in the FMC ?

In my case I had 373 FL Max and something like 365 FL for optimized. I then tried 370 FL for the step. This did not work. Maybe the algorithm compares the new step climb altitude to the optimized instead to the max level, so it essentially thinks no you can't go that high. Just guessing here. Will test that after christmas.

[Deleted Account]

It definitely was, but on the one try where it didn´t auto climb for me it also was, so I don't think this is the issue.

1 hour ago, FelixM said:

@gumbygerJust spot something. Is it possible that in your case your new step climb altitude was lower that the optimized FL in the FMC ?

In my case I had 373 FL Max and something like 365 FL for optimized. I then tried 370 FL for the step. This did not work. Maybe the algorithm compares the new step climb altitude to the optimized instead to the max level, so it essentially thinks no you can't go that high. Just guessing here. Will test that after christmas.

 

[WernerAir]

Nice idea, @FelixM.

Unfortunately I just had no success testing it - flight from SEQM to SPJC, Cruise level 350, max 399, opt 391. Step climb set to FL 370 - so way below both max and opt. As usual, P.Clb flashes in blue for a few seconds, then disappears. No climb until I initiate it manually. So I have to agree with @gumbyger that this is probably not the issue.