Estimated time for decent (Top of Decent, T/D, ToD)

1st Official Post

    The estimated or predicted time for the descent is in not correct. It shows allways the actual time in the FMS/MCDU on the VNAV or PROG pages.

    Boeing (B787)

    On the B787 you can also see that the T/D on the HSI is right in front of me. But on the ND the T/D is a little further away. Perhaps this has also something to do with the estimated prediction of the Top of Decent? Interestingly, the estimated arrival time is correct.


    Airbus (A321)


    Is it possible to fix this problem with one of the next updates?

    On eastbound transatlantic flights, the estimates don’t show the changeover in the day/night cycle. Thus, some progress pages can display flawed information such as « T/D: 2957Z »

    • Official Post

    The vertical display (VD) below the navigation display (ND) in the 787 shows the navigation route profile which doesn't take the airplane performance into account. Unfortunately I cannot change that. The FMS computes a different top of descent based on parameters set per aircraft and values that you enter into the FMS, such as the 250kt speed limit below 10000ft. The autopilot also only follows the FMS commands. That's why the vertical display may not match what the autopilot is actually doing.

    Regards,

    Jan