I try to create a short flight from New York to Boston using the FMC.My departure airport is JFK and arrival at KBOS ( Boston ).I aim at flying over twoVOR's ( DPK and ORW ) and then arrive in Boston.I entered the datas into the FMC but when turning VNav and LNav on onlyVNav gets illuminated.No reaction from LNav.Can anybody give me a hint of what I am missing ?Greatly appreciated.

First of all it depends what aircraft you are in, there are some differences in how the CDU operates on aircraft from various manufacturers, then of course it also depends who made the aircraft for FS and how closely it resembles the real CDU and FMC on the real aircraft.Without knowing any of that, it'd just be a guess as to what was missing. So I'll take a guess and say that you've either not got everything engaged on the mode control panel, or you've not got the navigation system set up properly to read your position, which could mean the aircraft doesn't know where it is and cannot therefore navigate in the horizontal plane because it does not know which way to turn to reach your waypoints, i.e. the INS/IRS isn't correctly aligned or possibly not engaged in its navigation mode. But as I say, without knowing the aircraft type and how realistic the FMC and CDU are emulated, it can only be a guess.Al

First of all it depends what aircraft you are in, there are some differences in how the CDU operates on aircraft from various manufacturers, then of course it also depends who made the aircraft for FS and how closely it resembles the real CDU and FMC on the real aircraft.Without knowing any of that, it'd just be a guess as to what was missing. So I'll take a guess and say that you've either not got everything engaged on the mode control panel, or you've not got the navigation system set up properly to read your position, which could mean the aircraft doesn't know where it is and cannot therefore navigate in the horizontal plane because it does not know which way to turn to reach your waypoints, i.e. the INS/IRS isn't correctly aligned or possibly not engaged in its navigation mode. But as I say, without knowing the aircraft type and how realistic the FMC and CDU are emulated, it can only be a guess.Al

First of all thanks for your reply.The aircraft is a Boeing 747-400 from PMDG and the IRS was aligned.The systemworks well when using a company flightplan but like I said when entering the waypoints manually there aresome problems.Just to confirm: On RTE1 it says: Via TOWhat I do is enter the name of the waypoints to TO and by dong so Via indicates direct.After that I execute and continue with all the procedures.At the end I select VNav ( light turns on ) and LNav ( no light shows )To me it looks I do something wrong when entering the waypoints but the question is what .James30

Okay, I recommend that you post the question in the PMDG forum further down the Avsim forums main page. I have the PMDG 747, but only for FS9 and not for FSX, so I think bearing in mind that there may just possibly be a sim-related quirk going on, it would be better for someone who has the FSX version to try and figure it out. As far as I'm aware there are no differences in the PMDG 747 for either sim, but I may be wrong on that, so I think your best bet is the PMDG-specific forum.If you don't get any help, I'll be happy to try and duplicate your plan and the steps you are making in the FS9 version later on (have to go out in a minute, I'm helping a friend to decorate [oh, deep joy} so can't do it right now, but I'll look on the forums later and see if you've got an answer, if not I'll give it a look).Al

Okay, I recommend that you post the question in the PMDG forum further down the Avsim forums main page. I have the PMDG 747, but only for FS9 and not for FSX, so I think bearing in mind that there may just possibly be a sim-related quirk going on, it would be better for someone who has the FSX version to try and figure it out. As far as I'm aware there are no differences in the PMDG 747 for either sim, but I may be wrong on that, so I think your best bet is the PMDG-specific forum.If you don't get any help, I'll be happy to try and duplicate your plan and the steps you are making in the FS9 version later on (have to go out in a minute, I'm helping a friend to decorate [oh, deep joy} so can't do it right now, but I'll look on the forums later and see if you've got an answer, if not I'll give it a look).Al

Are you aware that the PMDG support shows the following message:Customer support forum hosted by Avsim.comIn other words they have no forum or support and therefore refer to Avsim.comIn the mean time I continue to try and here is what I get: ( on the RTE pages ) Via To Direct DPK ( my first waypoint which is a VOR ) Direct ORW ( my second waypoint which is also a VOR ) Then I enter the Boston airport which is my final destination Direct KBOSAnd here an error message appears : Route DiscontinuitySo what do I do next ??Thanks

Are you aware that the PMDG support shows the following message:Customer support forum hosted by Avsim.comIn other words they have no forum or support and therefore refer to Avsim.comIn the mean time I continue to try and here is what I get: ( on the RTE pages ) Via To Direct DPK ( my first waypoint which is a VOR ) Direct ORW ( my second waypoint which is also a VOR ) Then I enter the Boston airport which is my final destination Direct KBOSAnd here an error message appears : Route DiscontinuitySo what do I do next ??Thanks

I just found the proper PMDG Forum which is on Avsim.My mistake.

I try to create a short flight from New York to Boston using the FMC.My departure airport is JFK and arrival at KBOS ( Boston ).I aim at flying over twoVOR's ( DPK and ORW ) and then arrive in Boston.I entered the datas into the FMC but when turning VNav and LNav on onlyVNav gets illuminated.No reaction from LNav.Can anybody give me a hint of what I am missing ?Greatly appreciated.

Did you check the legs page to see if there is a route discontinuity?

Did you check the legs page to see if there is a route discontinuity?

Before entering the last waypoint ( which is the Boston airport KBOS ) I getthe message: Route Discontinuity Could that be the problem and how do I solve it ?

Normally you would just go the Legs section and eliminate the discontinuity by (left) selecting KBOS and then (left) entering it again up above where the discontinuity is. Press Exec again after that to make sure everything is accepted.

Are you aware that the PMDG support shows the following message:Customer support forum hosted by Avsim.comIn other words they have no forum or support and therefore refer to Avsim.com

Are you aware that avsim hosts the PMDG support forum? http://forums1.avsim.net/index.php?showforum=136

Are you aware that avsim hosts the PMDG support forum? http://forums1.avsim.net/index.php?showforum=136

No,I was not.But now I am.

Are you aware that avsim hosts the PMDG support forum? http://forums1.avsim.net/index.php?showforum=136

I replied to the topic as a general FMC question so he wouldn't have to reveal his whole name. :(It could have happened with any decent FMC really.