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Guest DeanWermer

Maintaining programmed altitude

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Hello to all!!!!! I am having trouble with the aircraft maintaining the altitude that I program into the FMC. I use FSNAV to plan a flight plan, then print out the flight plan. To put into the FMC. But, prior to doing that I delete the info from FSNAV and exit out of that program. After I have entered the desired Dep/Arr rwys, and legs. I let the FMC tell me what altitude to set. I then enter that into the MCP and proceed with the flight. After I have attained the crz altitude the plane will level off. But, moments later the a/c will start to climb until it reaches an altitude almost 4000 ft from the programed one. This happened particularly on a flight that I did from KMIA to KSAN where the programed altitude was FL353. Prior to me arriving to the programmed descent I had climbed to FL394.I am sorry if this has been brought up before. I have limited time and really enjoy flying this a/c when I have the time.Thanks in advance for all of your help!!!!:-beerchugJohn

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John,the secret lies in the correct programming of the FMC. If you're used to programming other FMC's, then the procedures to correctly program our Flight Management Computer is slightly different. I myself am not an FMC expert so may I direct you to some excellant tutorials written by fellow simmers like yourself?pmdg_flight_tutorial_v2.zip and 737tngadvtut.zip both of which can be found in FS2004 Miscellaneous Files on the AVSIM forum.Following the examples set in either of these tutorials will have you nailed to your flight plan.

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If it is of any help:The MCP rules over all else.If you set and capture an ALT in the MCP window then unless you deliberately handfly away from it then the AFDS will keep you at that ALT, unless you get into a critically low speed situation, regardless of what VNAV wants to do. Certainly IRL it would never climb above the MCP ALT on the automatics.I do not us FSNAV so I may be on the wrong track for you.Note:A fundamental to understanding the AFDS is that the MCP selections/windows control the Flight Director and any of the 4 pilots aboard can follow the FD.. be it they either autopilot or either of soft squsihy ones.We set the MCP to tell the FD where we want to go and we then follow the FDs commands to get there. If you select VNAV then the FD will follow the VNAV PATH you have set up in the FMC ie it will climb to your cruise ALT or the next ALT restriction in the programmed flight plan but it will NEVER go past the MCP ALT window. ie you set CRZ ALT FL400 but MCP window is at FL280 (because that is all ATC have cleared you to) then the FD will tell the AP to climb along the selected PATH on the CLB page (ECON, MOD CLB, MAX RATE or MAX ANGLE) but only until it reaches the ALT in the MCP window.. it will then change to ALT HOLD mode until you set the MCP ALT higher for further climb and re-engage a vertical mode other than ALT HOLD ie VNAV, LVL CHG or VS.Hope this helps,Brad

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Pete and Brad,Thank You very much for your replies, and a little more enlightenment on the procedures. This truly is a fantastic a/c, and for me the pure joy of flying this bugger is learning something new about it everytime I fly it.Thx again!!!!Later,John

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JohnWhy not export your FsNav route as a PMDG ".rte" file? FsNav supports this with the plugin available on the PMDG website.It works great for me and the FMC even understands the speed/altitude constraints I input in FsNav. Simple, quick, GO FLY!RegardsAdam MooreRegistered PMDG 737NG Ownerwww.flightpix.tk

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