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Guest reyramon

LNAV and the Queen

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I know there have been other posts for problems with LNAV and the 744, but none of them specific to my problem. I purchased the Queen at the end of december. i made one quick flight but encountered a problem with LNav right away. I would engage it and it would fly its course to the waypoint. but once there it woudl circle and circle it until i entered the next waypoint(or deleted the current waypoint). so i figured this error to me not reading the manual fully. so here i am a month later and now the problem has "escalated". i've since read the manual several times. now LNAV will not even engage or arm. that is, when i click on LNAV, it does not stay lit, nor does the white lettered "LNAV" stay displayed for more than half a second on the F/D readout. I've tried flying directly over the magent flight path, but nothing. this is a great product and just want to fully enjoy it. Any help or suggestions would be appreciated. Thanks, Rey RamonAAVirtual.com

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Hello Raymond, To be able to help you out we need to be able to replicate exactly what you are trying to do. LNAV has criteria before it will even arm so please give us a rte and perhaps a screenshot of when you try to arm LNAV..[h4]Randy J. Smith[/h4]AMD 64 4000+|ASUS K8V DELUXE|SAPPHIRE ATI X800XT PE|MUNCHKIN 3200|80 gig SATA|DELL 1905FP 19" LCD|TRACKir PRO|PFC JEPPESEN MOONEY YOKE|CH PRO PEDALS|

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ok. i'll give an example using a simple flight form kdfw-kiah with only using lnav. first i set the reference airport on the position page. then i go to to the RTE page and enter kdfw and kiah into the orgin and destination airport. i then go on to enter the jpool departrue bilee transition, and the hoagi1 arrivale bilee transition agian. i activate the route at this point. then i go on to vnav and enter the data needed there, activate, and so on etc( entering gross weights and what not). so after i have the fmc set up, and flight director on, i'm ready to go i take off. after 1000 ft or so, i turn on my cmd autopilot. i activate hdg sel to interectp my flight path and try to arm LNAV by pressing it. a white lettered LNAV flashes just below the HDG SEL on the flight director display. but it last for a second or half a second instead of staying on and turning green when it engages. the light on the LNAV button does not even turn on. am i missing a step in fmc programing or something? do i need to do reinstall of the aircraft? i have the update installed. also i have the irs set to instantaneous. i've other addon aircrafts and the pmdg 737ng installed and work with out a hitch. i'll try and post screenies soon, but not much to look at. vnav actually does work, as do all other aspects of autopilot. ~Rey Ramon

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If hdg to intercept the path is not working (not sure why since I cannot see what is going on) try a DIR TO, this will work.[h4]Randy J. Smith[/h4]AMD 64 4000+|ASUS K8V DELUXE|SAPPHIRE ATI X800XT PE|MUNCHKIN 3200|80 gig SATA|DELL 1905FP 19" LCD|TRACKir PRO|PFC JEPPESEN MOONEY YOKE|CH PRO PEDALS|

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Rey,Are you getting any sort of message on the CDU like "NOT ON INTERCEPT HEADING"?

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I am having issues with LNAV aswell, after takeoff it does not proceed directly to the first waypoint. I made a clean FS install and problem solved, then I reinstalled my addons and the problem reappeared....

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Hello Tom, Without specifics there is no way anyone can help you out. For us to be able help you need to provide us with all the details. First wpt from? What wpt? SID? Provide us the ability to replicate you flight and we will be able to provide you a helpful answer to your issue.[h4]Randy J. Smith[/h4]AMD 64 4000+|ASUS K8V DELUXE|SAPPHIRE ATI X800XT PE|MUNCHKIN 3200|80 gig SATA|DELL 1905FP 19" LCD|TRACKir PRO|PFC JEPPESEN MOONEY YOKE|CH PRO PEDALS|

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Randy,I'll try to explain the situation. At Gibraltar (LXGB) RWY27, flight plan loaded for a flight to EBBR.Weather: Activesky 6No SID loaded, just selected RWY27 in the CDU, reconfirmed the first waypoint (a vor called MAR) I included a pic from my situation 5 minutes after departure. You can see the autopilot does not track the LNAV, and that's quite frustrating...I some other posts, it was suggested to reconfirm to direct waypoint, but that doesn't help either.Can you solve this please because it makes my Queen unusable... And I did not have this problem when the Queen was released, only with the V1.1 upgrade...

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Hello again Tom, The screenshot helps out greatly! For LNAV to engage in this situation (as the rl aircraft would) you need to point your aircraft in a direction that will "cross" i.e. intercept that magenta line you see on the ND. So, set your hdg to cross that path then select LNAV (push the hdg sel knob) you will notice after you push LNAV that the pilot's flight display annunciation (FMA) will show LNAV in "white" which means it is now armed and will intercept the path ;-) ............................Randy J. Smith.............................A PROUD MEMBER OF THE PMDG BETA TEAM[h4]Evolution is a process that results in heritable changes in a population spread over many generations[/h4]

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LNAV is engaged in his pic though - it's just flying with a 1.5nm crosstrack error... not really sure why.

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Mmm, I'm not really sure why either, but that's why I contact you ;)I believe it could be a conflict with a 3d-party software because with a clean install I did not have the problem...

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i get no message as far as not on intercept course. besides i usually use hdg sel to get there and then engage on all my other aircraft as well. mine does not even arm. i'm not sure what else to try. i'm still awaiting a download link so i can redownload and reinstall it to see it if will fix the problem.

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oh and as far as 3rd party installs, i do not know. i have not added anything new from when i first purchased it and it worked then. this was at the end of december. do you think it may be the update?

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Rey,Is this occuring on every flight? If so, I'm betting on a corrupted magvar file in your FS install or something to that effect.

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"Could it be the IRS is aligned to the wrong coordinate, hence everything is offset?"Armen...It's difficult to describe, but...The IRS's and radio updates (including GPS) create the background map on the ND. The (real) aircraft is designed to believe that map is real and will fly to the magenta line on that map, even if the background map is created from false data (such as wrong IRS entry).If the aircraft suddenly gets correct data, the background map and magenta track will shift quickly to one side.... and the aircraft (which is represented by the fixed airplane symbol), will try to "chase" the moving magenta track (by flying to the track in the real (outside) world).Hope this makes sense.Q>

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>Rey,>>Is this occuring on every flight? If so, I'm betting on a>corrupted magvar file in your FS install or something to that>effect.Ryan,Yes this is happening with every flight! Interesting thought of you, where can I find the original one? (which file),To the other poster: yes I always do full alignment with the correct coordinates.

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Only way I know of to fix that would be to uninstall and reinstall FS, it's embedded in the BGLs I believe...

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well i'm going to reinstall the queen tomorrow and see if it helps any. if not then i'll reinstall fs9 to see if that file gets copies right. i'll keep you updated.

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Not to get too far OT, but this might be a good place to ask. The EFIS MCP's buttonology almost seems to suggest that the airplane and the ND are working off different sources of present position data. Weird idea? Well . . Stay with me for a moment. I agree that the ND's 'map' is the present position reference for navigation, there's just something I don't understand about how a function or two works. There's a button on the EFIS MCP called "Pos"(tion). The button overlays the ND's aircraft position triangle with a horizontal bar (dog bone looking thing) for the updated GPS position. When you disable GPS updating, the symbol becomes a little three dotted airplane (looking thing).The question then becomes: So, the map is considered 'real' (the actual present position reference)and the triangle at the base of the ND simply represents the position of airplane relative to the map (This is similar to the 'painted onto the glass' function those little, bolted on horizontal coat-hanger-wire airplane symbols provided in those ancient, mechanical ADIs. It's essentially an airplane symbol bolted to the airplane's instrument panel that something moves around behind.) In other words, the "airplane" (the "you are here" triangle on the ND) doesn't have a position . . . other than to be 'painted on' to the back of the glass at the base of the ND. It's the ND's map that is displaying the present position data and that 'painted on' airplane just flys there. The airplane's position is 'fixed'. The airplane's position IS the triangle. It is literally that piece of glass.If this general understanding is accurate, then what's the purpose of the "Position" annunciation provided by the EFIS MCP?Here's a test flight I did before the patch. I flew a polar route just to get out of range of radio updating. (Just FYI, there

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Sam..... The laws of physics change at the MS poles ;) Ignore them.In real life...The triangle represents the FMC computed position. If the GPS is active, the FMC uses this position when navigating in high latitudes. If GPS is not available, then each ND switches to the onside IRU. i.e Captain's ND uses the Left IRU and the F/O's ND uses the Right IRU. The switchover from triple IRU to single IRU is fairly smooth. If the magenta line is racing away from you, then it will probably be a result of the global distortion in FS9.The aircraft should try to chase the magenta line (but this may depend on which magenta line we are talking about... the one on the Captain's ND or the one on the F/O's ND, which may show a difference in polar regions.On the real 744, if you manually tune bogus VOR's it means nothing. If there are two valid/local DME's in range, then the FMC will ignore the manually tuned VOR's and use DME stations (DME-DME updating). DME-DME updating has preference anyway. All you are doing by tuning bogus VOR's is preventing VOR-DME updating and stopping the "VOR" displays from working on your ND's. Pressing the POS button is showing you "raw data". It shows you where each (drifted) IRU thinks you are... i.e. by painting asterisks on the display... and where the GPS thinks you are...i.e. by painting >-O-< 's on the screen... and where the other nav radios think you are, by painting green lines from navaids (with bearing/distance info). If GPS is operating, then more likely than not, the GPS symbol will be will be sitting on top of the airplane triangle symbol. Priority is given to the GPS's by the FMC, so if LNAV is engaged, then the aircraft will chase the GPS symbols. Viewing raw data (by selecting POS) will tell you if something is out of whack. For example, you will see straight away if a single IRU is drifting away from the others.Hope this helps.Cheers/Q>http://forums.avsim.net/user_files/141341.jpg

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