I have the problem, when I insert a STAR and modify some constraints, the T/D point is gone. I have this problem only with CS products, this occurs in no other addon.

Yes, I know. I have the same issue. Its a big problem. In v4.4 we could erase a waypoint, click cancel and the T/D calculation came back again. This method doesnt work in v4.6 :( I just mess around with altitude constraints far down on the arrival / approach. That usually gives me a T/D, at least after messing with it for a while

I  tried to insert a STAR and modify some constraints as well.Getting the same problem.Do let me know if you get a solution.

Can you guys try to enter the STAR as soon as possible? Maybe even at the gate. It seems to make a difference if the FMC has some data to work with or if it gets it later.
It shouldn't make a difference on the real planes (unless you've already passed the TOD a long time ago), but it could in the sim rendition.

CoolP.

I think you missed what the actual problem is. ;)

The problem is when you modify the Altitude or Speed in a STAR, not just putting the STAR into the route. I can make some changes to TRANS, but I don't normally make changes to the STAR. So I'm not encountering this problem myself. It sounds like the Speed and Altitude constraints contained in the STAR may differ from those on the approach plate(s) and so they are modifying them.

Mark

Oops, right you are. He even states this in the first post, so I even fail to find an explanation now.  :-[ Lets get some coffee.  :D
By the way, can you guys please stop posting the wrong questions to my answers.  ;D

CoolP wrote on Dec 9^th, 2011 at 10:31am:

By the way, can you guys please stop posting the wrong questions to my answers.  ;D

:D ;D

Sometimes the FMC just randomly reprograms itself.  The speeds/altitudes change and the T/D is lost.  At this point you might as well hit the ESC key because the flight is lost. :'(

Sounds reasonable, theguz. However, try to describe the circumstances as close as possible. Remember, the folks are working on a 777 too, so maybe it helps avoiding some things and understanding the ones on the current planes.
To get rid of the 'need' to exit the flight, just use the descent calculations from the old school flying. It is a rough workaround only, no doubt, but it gives you an approach and, most likely, a happy landing in the end. The folks in the 707 and 727 always work that way, so it's not too uncommon.

So today I'm flying from KSAN to KSFO.  Things are looking good.  I'm step climbing holding the ALT with the hold when I get to each waypoint.  The VNAV is working well not overshooting the altitudes so I don't need to use the ALT HOLD much on ascend.  I get a T/D and I start to descend again holding the altitude with the ALT button at each step.  Then I resume VNAV at 20Kft but the bird does not want to descend.  I'm not sure why.  So now I have to take over with the ALT hold with the V/S and flying becomes a chore.  So I'm not sure why the VNAV stopped descending.  Was it because I was holding it at each step?  Did it forget what it was doing?  Do I need to just let it be?  Help! :-/

Hi theguz.

I use VNAV all the way down. If there are altitude or speed constraints, I find that the 757 obeys them when using VNAV. The ones that create the problems (if at all) are the altitude constraints that have, for example, 17000A at the end of them (be at 17000 or Above at the waypoint. So why don't you let VNAV control the descent?

I have found that it is more likely to exceed an altitude constraint during the climb phase than during the descent phase.

Mark

You would think that holding ALT at each step descend would not cause a problem for the VNAV but whatever.  Next flight I can adjust my ALT HOLD to zero and let the VNAV do all the vertical flying until glideslope intersection.  The VNAV is a little erratic on the way down, sometimes it will overshoot and then climb for a bit which causes me a small amount of panic ("why are we climbing!?").  It often times will reach the waypoint altitude prior to the waypoint again causing me to scratch my head.  I'm not using the 8000A designators anymore since they are ambiguous.  I hope to become a better flyer. ::)