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Ibanezmatt13

Very strange descent issue!

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Hi,I have just purchased the MD-11 aircraft and I am experiencing some minor but rather frustrating issues. When I am nearing the end of the cruise and about to start the descent I arm the descent profile for a lower altitude in readiness for the profile descent. At top of descent it begins descending as expected. In other aircraft such as the NGX when I turn off prof it will show a marker on the ND of where I will level at my imputed altitude with my current vertical speed. So basically I want to be able to decide where I want to end up depending upon my v/s.In the MD-11, I can alter my vertical speed, but I have absolutely no idea when I am going to reach that level becuase there is no marker showing me this on the map.I hope somebody can understand what I am trying to say and please help me before the Cross the Pond event on Saturday!Many thanks in advance.Matthew :(

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Matthew,the MD-11 does not have this arc showing where you'll level off.I suggest you fly the two tutorial flights before crossing the pond if you haven't already done so...Markus


Markus Burkhard

 

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The MD11 is not a Boeing and that shows in many different ways. One of them (as you have found) is that you do not adjust your vs to arrive on target, you specify your target and let the VNAV sort itself out. You have already told the FMC what speed you want to desend at, and you have told it what Cost Index to use, so why would you want to ignore that by manually playing with the vs? Just tell the FMC you want to be at such and such a waypoint at a given height and speed (and even at a given time) and it will work out the appropriate place to start descending.(And follow the advice Markus gave you, do the tutorial flights.)


Paul Smith.

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Hi,Thank you very much for your early reply. Last night I completed a flight successfully in the MD-11. The only thing that was getting at me was the fact that if I was on Vatsim and they told me to descend to be level before such a waypoint or be level in 30 miles, I just wondered whether the MD-11 had that extra degree of accuracy. However, I thank you for your feedback and I'll follow that tutorial flight as well. I believe there is also an advanced tutorial pdf that can be downloaded from PMDG's website; am I right?Also, I didn't think the cost index was simulated in FSX. Is it?Have a great day.Matthew :)

The MD11 is not a Boeing and that shows in many different ways. One of them (as you have found) is that you do not adjust your vs to arrive on target, you specify your target and let the VNAV sort itself out. You have already told the FMC what speed you want to desend at, and you have told it what Cost Index to use, so why would you want to ignore that by manually playing with the vs? Just tell the FMC you want to be at such and such a waypoint at a given height and speed (and even at a given time) and it will work out the appropriate place to start descending.(And follow the advice Markus gave you, do the tutorial flights.)
Matthew,the MD-11 does not have this arc showing where you'll level off.I suggest you fly the two tutorial flights before crossing the pond if you haven't already done so...Markus

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CI makes a big difference, but remember that it is aircraft specific. In the MD11 you should be using values around the 80 (down to 50 and up to 100 are still reasonable). In the NGX you would use values around 30 (plus or minus 15). If a controller asks you to be at a waypoint at a certain altitude, just enter the appropriate restriction into the FMC. VNAV will do the rest for you (including telling you that it can not be acheived.)


Paul Smith.

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Hi,Thank you very much for your early reply. Last night I completed a flight successfully in the MD-11. The only thing that was getting at me was the fact that if I was on Vatsim and they told me to descend to be level before such a waypoint or be level in 30 miles, I just wondered whether the MD-11 had that extra degree of accuracy. However, I thank you for your feedback and I'll follow that tutorial flight as well. I believe there is also an advanced tutorial pdf that can be downloaded from PMDG's website; am I right?Also, I didn't think the cost index was simulated in FSX. Is it?Have a great day.Matthew :)
In the example you gave here, the easiest way would be to create a custom waypoint in the FMS and insert the altitude into that custom waypoint you just created for whatever speed and/or altitude that ATC gives you (just as you can do in the Boeings). To read up on how to do that open the 'PMDG MD-11 Flight Management System Operating Manual > Advanced Flight Planning > Waypoint Creation and F-PLN Entry (Page FMS.100.1). What you want is a Place/Bearing/Distance waypoint (also called an Along-Track-Waypoint). You can, more or less, create a waypoint for just about anything you may get assigned or fly based on a chart (even though it may not be a real waypoint - you can create a custom one!).The MD-11 operates very similar to the Boeing's once you actually get used to it (the comparisons will start to come together as you get more familiar with the MD-11; they just liked to name things differently). I'd say the FMS & Autopilot are probably the most difficult things to get used to, especially using it for the first few times. Spend some time in the FMS Manual and Tutorials and you'll get the hang of it in no time. Also, there is a Boeing to MD-11 comparisons document that PMDG created that you can read through and help with your transition. I believe it is included as a section in one of the User/Operating Manuals for the MD-11.Bottom line - don't get discouraged! Once you get her down she is a beauty and a blast to fly (and even more rewarding!). I've had multiple people tell me they'd love to fly her but they "don't have time to learn it". It isn't as hard and daunting as it seems! After flying her quite a bit I'll get back into the PMDG 737s and 747s and it just seems so boring and simple compared to the MD-11! You've been warned - she'll keep calling you back for more!

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I believe there is also an advanced tutorial pdf that can be downloaded from PMDG's website; am I right?
Indeed, it is available in the download section. It contains plenty of additional information and ends with a non-precision approach. I recommend you give it a go!Regards,Markus

Markus Burkhard

 

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