Step Climbs Above Max ALT

[wde12 19]

Hi all,

Question for the board. Standard disclaimer: here at work, so I don't have access to the FCOM and a forum search yielded nothing.

I was flying a Cathay 77W from EGLL to VHHH. One thing I will do is hit the "crew rest," meaning a disconnect from VATSIM, turn off random failures, and shut down or disable anything that could interrupt Otto from taking the bird along its route. I go to bed, wake up, and when I come down from the proverbial crew rest, I have about 2 hours to go. 

I have auto-step climb enabled. I can't remember specifics, but I want to say my ZFW was around 226 tons. The initial cruise alt was FL310. This morning, the MCP ALT was set to FL330. I was surprised to only see one step climb, but was further surprised when I noticed my actual cruising altitude was FL400. There were no overspeed warnings, but there was truly no gap between the yellow lo speed / stall tape and the dotted red overspeed. When I went to the CRZ page, the Max ALT was like 36,500. The optimum altitude was indeed 40,000. 

Does anyone have an idea as to what happened (i.e., what I did wrong)? I didn't expect the FMC to calculate an optimum altitude above the max, nor did I expect autoflight to step climb up despite this limitation. Finally, I'm scratching my head as to why I was at 400 when the MCP ALT read 330.

I realize there is a lot of missing info but I hope this is enough.

And for those that feel the need to chime in "well, this is why you don't leave the flightdeck unattended" ... save us all the eye rolls and move on to the next topic.   

Edited June 4, 2018 by wde12

[Budbud 227]

Hi,

I don't use the auto step climb feature but I'm fairly sure that the MCP altitude and the cruise altitude should match. Also the OPT FL above the MAX FL is not normal either.
Without more info, I would check two leads, the weather in the leg data page (temp and winds) and the panel state.

Which panel states did you load the aircraft with? And which weather data did you use to fill the leg data page?

Also, do you have any third party addons that could interfere with the sim (proATC for instance)?

[wde12 19]

Thanks for the insight. Let's see - for weather I use AS Next. Live config. I import the flightplan from PFPX and configure in AS to give me that weather "tube" and ensure winds aloft datalink is accurate. I think you could be onto something though. I loaded the winds during preflight but at the last second, edited the weather with a nasty set of conditions for takeoff. Then about 15 minutes after takeoff, I reverted back to live weather. I don't remember reloading the winds in the legs page after this, and I am thinking this back n forth could have screwed something up.

As for panel state, I normally load the default cold n dark. Hold CDU Menu, empty the payload and fuel to about 10 tons, then plug in ground power and go from there. I don't care how RW pilots always arrive to a lit n' powered plane. The 777 and 747 startup sequences that PMDG models simply never gets old. 

The only other third party app I had running was Navigraph Charts, which simlink showing my plane position on the moving map. Otherwise, everything was closed.

[Budbud 227]

You can then try to perform a flight without messing with the weather.
Also you can try to perform a flight with loading the aircraft with the default panel state (the one with engines running) to rule out any issue with corrupted panel state (for that, move all the panel states but the default one from the panel state folder).