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Yoshimi

744 VNAV

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Hi to all, and excuse me for my bad English...I have two problems: if I start my flight from LIME, after programming the FMC, I don't reach to insert the LNAV, while in every others airports ther are no problems.The other problem, regards the VNAV: during the flight the LNAV works perfectly, but I must make the climb and the descent using v/s speed and alt hold...Anyone can help me? Many TanksYoshimi

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Guest Buck Bolduc

>Hi to all, and excuse me for my bad English...I have two>problems: if I start my flight from LIME, after programming>the FMC, I don't reach to insert the LNAV, while in every>others airports ther are no problems.>The other problem, regards the VNAV: during the flight the>LNAV works perfectly, but I must make the climb and the>descent using v/s speed and alt hold...>Anyone can help me? Many Tanks>>YoshimiThat happend to me. I forget the airport but it was a South American airport. After takeing off I had no megenta line to the first waypoint. I could see the first waypoint in plan mode, some 150-200nm away.It must be the airport is not in the airac database???Don't really know, stopped flying from there.

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Guest D17S

These sound related. Vnav needs a complete Lnav route. It there are problems with an Lnav destination, Vnav might not be able to generate any inroute altitudes. If Vnav doesn't have an Lnav destination to guide to, it won't be able fly a vertical profile to that spot . . . because it doesn't exist (in it's FMS universe).The Lnav situation needs to be stabalized first, then at least Vnav will have a chance.

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Hi Buck, the airport is in Airac database... Thank YouYoshimi>>That happend to me. I forget the airport but it was a South>American airport. After takeing off I had no megenta line to>the first waypoint. I could see the first waypoint in plan>mode, some 150-200nm away.>It must be the airport is not in the airac database???>>Don't really know, stopped flying from there.>

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Hi Sam,what do you mean for "complete Lnav route"? The waypoints,the headings, the altitudes and the speeds in flight plans are ok: how I can make? Many thanksYoshimi

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Guest D17S

Hi Yoshimi, I understood you to suggest that Vnav would not even engage. The Vnav button never lit up. Is that right? If so, then one problem might be that you did not have an arrival runway selected. Look in the legs page and make sure your destination runway is shown there. It may not be the last entry beause your flight plan might have included a missed-approach HOLD waypoint. Also notice that on the right side of your destination line is your destination runway's field elevation. This runway is your Lnav's "lateral destination." This field elevation is your Vnav's "vertical destination." Vnav must have this 'destination' to work, Sounds like there might be a problem with that particular airport destination waypoint you are trying to fly to. If there's some sort of a software problem with that waypoint (maybe an altitude was not properly assigned to it in navdata's AIRAC programming setup), it could cause the Vnav function to mess up.So, let's troubleshoot. Does the Vnav function work for other flight plans? Use FSBuild or FS Navigator (with the export module) to build and export a flight plan to PMDG. Load this flight plan from the FMC's "ACT RTE 1" page using the "Co Route" line. Go through the rest of the FMC setup drill, then page back through all the setup pages for any unfilled boxes. Fill 'em all up with something. The FMC won't let you mess up too badly. Make sure the "exec" button lights up and you press it (as many times as it wants!). Then check the 'Legs' and 'Vnav' pages for "problem" messages. Fix 'em. Turn on the Flight Director. Vnav will arm on the ground if all's OK. If the Vnav button will not light up when you press it on the ground, something is still wrong. If you arm Vnav on the ground, after takeoff it will engage at 400 feet. Watch the pitch window. It will go from TOGA to VNAV SPD. The FMC will now communicate with you by controlling the pitch command bar. You can follow the FMC's Vnav guidance by just following the command bar . . . or just press an autopilot button and go get a cup of coffee.I think the Vnav functions is actually harder than Lnav to deal with. Keep trying. This sim is a very real deal and has a corosponding very vertical learning curve. It'll work eventually.Let us know how it's going.

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