Results 1 to 8 of 8
  1. #1
    Eddie Armaos
    Guest

    Vnav Descent Again.....

    Hi,

    first i want to thank you, i was not remembing this section in ini file for
    :[VNAV], DescentSpeedControl=On

    So i entered "On", value and i made a very nice test flight from LGTS
    Makedonia to LGKR Kerkira airport with "bad" weather!!


    But i had a problem : Even if in T/D i dialed a lower altitude, from 28000
    to 12000 and i was with VLAN & LNAV modes, after the T/D announced from
    PmSounds, the aircraft didn't start the descent and i had to push the
    descent now command in FMC/Descent page.
    In Eicas screen i had the CRZ indication and i could not command the
    throttles of course, as i was in FMC Speed.

    No errors in widefs log files.

    I will retry a second flight, but i just post it, in case enyone can
    imagine
    a possible reason for this, or if anyone has the same problems.



    regards


    Eddie


  2. #2
    Enrico Schiratti
    Guest

    Re: Vnav Descent Again.....

    > first i want to thank you, i was not remembing this section in ini file
    > for
    > :[VNAV], DescentSpeedControl=On


    Good.

    > But i had a problem : Even if in T/D i dialed a lower altitude, from

    28000
    > to 12000 and i was with VLAN & LNAV modes, after the T/D announced from
    > PmSounds, the aircraft didn't start the descent and i had to push the
    > descent now command in FMC/Descent page.


    How much did it display in NM to the Top Of Descent on the CRZ page when
    that happened?

    Ciao

    Enrico


  3. #3
    Andras Kozma
    Guest

    Re: Vnav Descent Again.....

    Enrico,

    > :[VNAV], DescentSpeedControl=On
    > Good


    Scratching my head here, but you must be aware that the setting does NOT
    change anything.
    When DescentSpeedControl=Off is set the pilot should control the descent
    speed with throttle and the A/T should not be interfering. But it DOES
    interfere and MCP SPD is getting clearly annunciated...

    regards
    Andras.


  4. #4
    Enrico Schiratti
    Guest

    Re: Vnav Descent Again.....

    Hello Andras,

    > interfere and MCP SPD is getting clearly annunciated...


    What do you mean by anunciated... you do not want it to be anunciated?

    I will check whatever comes my way with the MCP when I come back, I am
    currently doing something completely unrelated to that.

    The DescentSpeedControl=Off is the one that should make the difference, i.e.

    once you set the thrust lever to IDLE and the thrust has gone back you
    should be able to compensate for thrust yourself.

    Also, please note that this does *not* apply when making an early descent
    and the vertical speed is locked at 1000 ft/min (or 1250 ft/min on the
    747).

    Ciao

    Enrico

    "Andras Kozma" wrote in message
    news:269222.53400@wb.onvix.com...
    > Enrico,
    >
    >> :[VNAV], DescentSpeedControl=On
    >> Good

    >
    > Scratching my head here, but you must be aware that the setting does NOT
    > change anything.
    > When DescentSpeedControl=Off is set the pilot should control the descent
    > speed with throttle and the A/T should not be interfering. But it DOES
    > interfere and MCP SPD is getting clearly annunciated...
    >
    > regards
    > Andras.
    >



  5. #5
    Andras Kozma
    Guest

    Re: Vnav Descent Again.....

    Hi Enrico,

    > What do you mean by annunciated... you do not want it to be annunciated?


    During the path-descend the MA shows the ARM annunciation (talking about
    737 here, might be different with others), and it doe it initially. But
    after some time it reverts back to FMC SPD, that I tried to say, perhaps it
    wasn't clear, sorry.

    > I will check whatever comes my way with the MCP when I come back, I am
    > currently doing something completely unrelated to that.


    Great, please have a look when got the time, this is the a most disturbing
    thing when trying to fly on the 'realistic' side...

    > The DescentSpeedControl=Off is the one that should make the difference,
    > i.e.
    > once you set the thrust lever to IDLE and the thrust has gone back you
    > should be able to compensate for thrust yourself.


    In theory, yes. That's what I was trying to explain. But the switch is not
    working. The behavior remains the exact same regardless of this ini switch.

    > Also, please note that this does *not* apply when making an early descent
    > and the vertical speed is locked at 1000 ft/min (or 1250 ft/min on the
    > 747).


    I would exaggerate if I said I understand what you mean...
    In PATH mode the A/T should be in armed mode, hence the pilot is able to
    adjust the throttle manually. The problem is that it reverts to FMC SPD, so
    no manual input is possible.

    regards
    Andras


  6. #6
    Andras Kozma
    Guest

    Re: Vnav Descent Again.....

    Hi Enrico,

    Sorry, I'm back to this nasty problem again...
    I tested the entire scenario this afternoon. At least I was able to nail it
    down.
    Yes, the routine (or whatever it is in this case) doesn't work. In
    VNAV-PATH
    mode the pilot doesn't get the throttle control back. It momentarily stays
    in ARM mode, but then reverts to the unwanted MCP SPD mode and no manual
    control possible anymore. Needless to say that it shouldn't be like this,
    and frankly (in the 737 at least) it makes a normal VNAV-PATH descent
    almost
    impossible.

    I tried out all PMmcp versions back to the beginning of this year, and
    found
    that the last version it worked PERFECTLY with, was mcp379, the exe dated
    2.29.2004.
    It just works as it should, in both path and speed modes. So something got
    broken in one of the early-spring 2004 versions and it stayed the same.

    Frankly, I wonder, how it was possible, that many of our fellow Boeing
    flyers didn't notice it for almost a year...
    Please have a look whenever possible, this is a very important thing for
    reality...
    Oh yes and I understand what you have said, that it does *not* apply when
    making an early descent and the vertical speed is locked at 1000 ft/min,
    yes
    true, but that is a special case. What I'm talking about is the plain old
    general vnav-path descent.

    regards
    Andras


  7. #7
    Michel Vandaele
    Guest

    Re: Vnav Descent Again.....


    Hi Andras,

    > mode the pilot doesn't get the throttle control back. It momentarily

    stays
    > in ARM mode, but then reverts to the unwanted MCP SPD mode and no manual
    > control possible anymore. Needless to say that it shouldn't be like this,
    > and frankly (in the 737 at least) it makes a normal VNAV-PATH descent
    > almost
    > impossible.


    Just for you info. The principal in the B744 is the same. There are just
    other annuctions in the PFD thrust box.
    Instead of ARM, IDLE should come up during the time the trottles are coming

    to idle and then HOLD must be annunciated, which means that the servos are
    now disconnected from the trottles and that the pilot can intervain
    manually. Of course A/T stays on. (At present stage this is not yet
    implimented in PM, but I suppose now that we are come more and more to type

    specific things in PMSystems, this important AFDS annuciations will follow
    too).

    But also for the B744 the VNAV logic doeqn't seems working (Sorry I didn't
    test it for a long time as my B744 project was underconstruction).

    Ciao

    Michel
    --
    Michel VANDAELE
    Member of the board FSCB
    EBOS2002 Designteam
    My B744 simulator project
    http://users.pandora.be/michel.vandaele/sim1.htm







    > I tried out all PMmcp versions back to the beginning of this year, and
    > found
    > that the last version it worked PERFECTLY with, was mcp379, the exe dated
    > 2.29.2004.
    > It just works as it should, in both path and speed modes. So something

    got
    > broken in one of the early-spring 2004 versions and it stayed the same.
    >
    > Frankly, I wonder, how it was possible, that many of our fellow Boeing
    > flyers didn't notice it for almost a year...
    > Please have a look whenever possible, this is a very important thing for
    > reality...
    > Oh yes and I understand what you have said, that it does *not* apply when
    > making an early descent and the vertical speed is locked at 1000 ft/min,
    > yes
    > true, but that is a special case. What I'm talking about is the plain old
    > general vnav-path descent.
    >
    > regards
    > Andras
    >



  8. #8
    Andras Kozma
    Guest

    Re: Vnav Descent Again.....

    Hi Michel,

    > Instead of ARM, IDLE should come up during the time the throttles are
    > coming to idle and then HOLD must be annunciated, which means that the
    > servos are
    > now disconnected from the throttles and that the pilot can intervain
    > manually. Of course A/T stays on. (At present stage this is not yet
    > implemented in PM, but I suppose now that we are come more and more to
    > type specific things in PMSystems, this important AFDS annunciations will


    > follow
    > too).


    In the 737 when a 'normal' VNAV PTH descent is done the first (and short)
    annunciation is RETARD and very soon it reverts to ARM. What I understand
    from your description, the 747 is the same just the annunciations are
    different. But those can easily be changed in the aircraft file, so in case
    the 'normal' routine worked again (and I truly hope Enrico will just need a
    short look to make it work again - as it WAS working once) the very same
    logic stands for the 747 as well.

    regards
    Andras


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