PMDG problems

[EHM-1058 Jörg]

Hello, i have started to fly with the B737-800 PMDG it is great. But i have a big problem to get the correct climbrate. I plan my flights with FSNAV 4.7 and export then to PMDG. When i activate the flightplan everything thems ok, but after take off the climbrate rise up and i get a stall. The other thing is the descent procedure when i pass the point to go from crz to des nothing happens. Please could somebody help me.
Regards Hardy (EHM1058)

[EHM-0948 Bruno]

I am sorry but i cannot help.

I also have the problem related to the CRZ to DES mode. Maybe someone can help us...

[EHM-0654 Murray]

Oy vey... How about the moon from the sky while I'm at it

First things first... RTFM, especially the FMC chapter, the docs are your best friend with the PMDG...

EDIT: Since I have been reading "official" FMC documentation and using the Project Magenta glass cockpit software, I have gotten used to using "official" abbreviations for stuff to do with the 737 cockpit. If any of what follows doesn't make sense, just ask and I'll write up a quick glossary of terms...[/i]

FURTHER EDIT: and of course I am assuming you want to do full-on CAT IIIA (FMC pretty much the whole way) here.[/i]

To be honest, I don't use FSNav as more than a moving map any more (even when I'm flying tours...). Entering the route directly into the FMC (Project Magenta in my case, but the PMDG one is almost as good...) is by far the easiest way to do such things, especially if you want the FMC to do all the hard work, as it [the FMC] leads you logically through the pre-departure programming.

Any how, as far as getting the climb and cruise alt right, you'd normally set these after entering the route - basic programming order from "cold" is POS INIT, ROUTE, DEP/APP, PERF INIT and LIMIT - the important pages are PERF INIT and LIMIT...

PERF INIT is where you specify the cost index (which despite what I have read elsewhere the PMDG FMC does take note of, enter CI of 500 and the autothrottle will do it's damnedest to get you to your destination in the shortest amount of time!) and cruise alt (TRIP/CRZ ALT by LSK1R, the value on the left is the calculated ECON cruise)

LIMIT (and there are three or four separate page groups for this) is where you specify things like flap setting for takeoff, climb profiles, N1 limits, and calculate the V-refs and so on.

Any time you see square boxes in the FMC, it is expecting an input from you (as the pilot). As mentioned above, the docs tell you all this...

Finally, once you've got a fully programmed FMC, set the MCP (autopilot) for takeoff - HDG should be runway heading, ALT is your initial alt (as given by ATC) or cruise alt if you've not been given an initial alt. Turn on the F/D, arm the autothrottle, and when you get take-off clearance, turn on TOGA (top left screw on the MCP) and when you hear "rotate" pull back on the control column and hand fly to your first waypoint (you can enable VNAV during the climb out). Once you are close to your first waypoint, enable LNAV and CMD A and let the computer take over...

And regarding FMC DES, you must have entered the altitude you want to descend to long before you get to the computed T/D.

[EHM-0654 Murray]

Originally posted by bfalcao
I am sorry but i cannot help.

I also have the problem related to the CRZ to DES mode. Maybe someone can help us...

Bruno, see the end of my post above

Basically, you have to enter the altitude you want the FMC/MCP to descend to on the MCP at least 25nm before the calculated T/D (on the ND... the PROG FMC page will tell you distance and time to T/D once you reach CRZ)

If, during DES, the FMC tells you "DRAG REQ", deploy speed brakes (just use "/", the PMDG logic knows to deploy the in-flight speed brakes...) and if the FMC tells you "DES PATH UNACHIEVABLE" or similar, you'll have to manually dial in more V/S on the MCP and hand/MCP-fly the descent until you get back to the FMC's descent profile and can re-enable VNAV...

[EHM-1500 Jim]

Agree with murray - i have FSnav but also only use it as a moving map. The FMC is much better and if you use the on-line route finder http://rfinder.asalink.net/free/ then it will give you the route as it is entered into the FMC. As for the descent, as murray says make sure you change the autopilot altitude before the descent or the plane will just carry on flying at your cruise altitude until you run out of gas!!

[EHM-0948 Bruno]

Ok Murray, thanks!

I am going to test it this evening ...

[EHM-0948 Bruno]

Hi,

After testing it, it started descent but it didnt changed from "CRZ" to "DES" mode.... I don't know if it had to be this way, but I thought so...
Also he descent to 10000ft. It was correct because it was the value that I inputed on the AutoPilot.

Also, I don't know how can I tell him to only descend when he is at a distance that can descend at 1800ft/sec ... That means that he should start descend from 100 nm from the destination. Normally he starts descend much more far away ....

[EHM-1570 Bruce]

Hi Bruno

If you want to descend at a later point, then do not change your altitude setting on the autopilot, otherwise the aircraft will start it's descent at the TOD, allow the aircraft to fly to the distance from the airport that you want to start the descent allowing the aircraft to fly at your present altitude, then change the altitude setting, if the descent does not start, go to the DES page, press the ARR key, then press DES NOW and the descent will start, it may happen that you will get the Descent Path not Available in which case you will have to set the descent rate manually.

[EHM-0948 Bruno]

Ok Bruce, will try again.

[EHM-0654 Murray]

Originally posted by bfalcao
Also, I don't know how can I tell him to only descend when he is at a distance that can descend at 1800ft/sec ... That means that he should start descend from 100 nm from the destination. Normally he starts descend much more far away ....

Bruno,

Ordinarily, the FMC operates PATH DES (will follow LNAV at the expense of speed) hence it starting it's descent much further out.  If you want a higher rate descent you can switch it into SPD DES (it tries to maintain MCP SPD at the expense of maintaining the vertical profile), or use the MCP alone to fly the descent (using V/S and LVL CHANGE) - or even fly the DES phase manually

NOTE: I could be wrong on this of course. I only have my FMC user guide with me at work, and it's DES section is very long and rather confusing...

[EHM-1058 Jörg]

Dear Pilots, thanks for all the information. it is true that nearly everything is written in the manual. But sometimes it is usefull to have one or two other meanings to solve problems.
Thanks a lot and see you in the sky.
Hardy