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rhodges

340-300 FMC/Autotracking flightpath problem?

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It has been quite some time since I made a flight with the PSS Airbus 340-300, so I thought I would go back to this good old bird in FS9 and carry a bunch of burocrats from Washington to Dubai to Help (They probably would confuse their problems even more to say the least). I do not remember ever seeing the following problem in times past.Note that I am creating my flightplan in FSC, useing ASA weather, and PFE/PF2000 ATC. These flights have been tried over the last three days.1. PSS Airbus 340-300, SwissAir livery.2. Flightplan: KIAD-OMDBSID: Capital One - ANNGE-Swann-EnoJ191-Davys-J42-BosNAR N79B-Allex-YQXTrackT-YQX-Kobev-50/50-52/40-53/30-54/20-Dogal-Baban3. First flight: Climbout and interception of the flightpath was normal, FMC/ATC tracking and waypoint acknowledgement/advancement also worked flawlessly until reaching one of the long/lat waypoints over the Atlantic. At that point, HDG control switched to my current numbered heading and automatic tracking (LNAV?) could not be re-engaged. NOTE: Automatic tracking was fine at all waypoints previous to this point including Swann, Annge etc. I would think this would negate those waypoints as being corrupt, however in the following flights the same problem occured at previous waypoints that were fine on this flight.4. Second flight: Same scenario on a different waypoint where automatic tracking ceased and control switched to my current heading. Sorry, but I do not remember for sure which waypoint it was, but I believe I made it across the Atlantic before the problem occured.5. Third flight: Same scenario except when reaching the Swann waypoint the same thing happened. 6. Fourth flight: Same scenario repeated exactly at Swann. Automatic tracking switched to my current heading and the flightpath continued thereafter on that heading. I could not change it back to automatic tracking. I turned the Autopilot off and tried again and all existing control settings remained including the heading selection.7. Fifth flight: Deleted the Swann waypoint in my FMC. This time, automatic tracking switched to my current heading at the Annge waypoint.8. Sixth flight: Simply turned the automatic pilot off, and went to "World>Go to Airport" in the FS9 options and put my aircraft back on RWY 19R. Reloaded the flightplan in the FMC. Automatic tracking switched to my current heading at Swann again and remained there.In each case, my FMC shows that I have reached the waypoint in question and colors change indicating the next. My Navigation Display ("ND") also switches to the next waypoint as would be normal. However, the Autopilot negates the automatic tracking and switches to my current heading. Automatic tracking cannot be re-engaged.Has anyone had this same experience and if so, possibly found the cause and hopefully a solution?Thanks:RTH

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It has been quite some time since I made a flight with the PSS Airbus 340-300, so I thought I would go back to this good old bird in FS9 and carry a bunch of burocrats from Washington to Dubai to Help (They probably would confuse their problems even more to say the least). I do not remember ever seeing the following problem in times past.Note that I am creating my flightplan in FSC, useing ASA weather, and PFE/PF2000 ATC. These flights have been tried over the last three days.1. PSS Airbus 340-300, SwissAir livery.2. Flightplan: KIAD-OMDBSID: Capital One - ANNGE-Swann-EnoJ191-Davys-J42-BosNAR N79B-Allex-YQXTrackT-YQX-Kobev-50/50-52/40-53/30-54/20-Dogal-Baban3. First flight: Climbout and interception of the flightpath was normal, FMC/ATC tracking and waypoint acknowledgement/advancement also worked flawlessly until reaching one of the long/lat waypoints over the Atlantic. At that point, HDG control switched to my current numbered heading and automatic tracking (LNAV?) could not be re-engaged. NOTE: Automatic tracking was fine at all waypoints previous to this point including Swann, Annge etc. I would think this would negate those waypoints as being corrupt, however in the following flights the same problem occured at previous waypoints that were fine on this flight.4. Second flight: Same scenario on a different waypoint where automatic tracking ceased and control switched to my current heading. Sorry, but I do not remember for sure which waypoint it was, but I believe I made it across the Atlantic before the problem occured.5. Third flight: Same scenario except when reaching the Swann waypoint the same thing happened. 6. Fourth flight: Same scenario repeated exactly at Swann. Automatic tracking switched to my current heading and the flightpath continued thereafter on that heading. I could not change it back to automatic tracking. I turned the Autopilot off and tried again and all existing control settings remained including the heading selection.7. Fifth flight: Deleted the Swann waypoint in my FMC. This time, automatic tracking switched to my current heading at the Annge waypoint.8. Sixth flight: Simply turned the automatic pilot off, and went to "World>Go to Airport" in the FS9 options and put my aircraft back on RWY 19R. Reloaded the flightplan in the FMC. Automatic tracking switched to my current heading at Swann again and remained there.In each case, my FMC shows that I have reached the waypoint in question and colors change indicating the next. My Navigation Display ("ND") also switches to the next waypoint as would be normal. However, the Autopilot negates the automatic tracking and switches to my current heading. Automatic tracking cannot be re-engaged.Has anyone had this same experience and if so, possibly found the cause and hopefully a solution?Thanks:RTH
I have to admit the plane has never done this to me. Some ideas do occur, however - first, validate the flightplan by checking all waypoints in your nav database; if FSC (I use FSB) and the PSS db's don't match it could give some problems. Second, turn off ATC. Third, turn off ASA. Also, start the flight in the default Cessna and then change planes and load the flightplan. The idea is to reduce the number of variables and to make sure the plane initializes properly.The problem pretty much (IMO) has to be in the nav data...DJ

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Thanks DJ. I will check out your suggestions. I highly suspect that you are correct that there is some conflict between the data bases. The thing that really puzzles me is that some of the waypoints were tracked with no problem on some trials, and didn't at others. I would have thought it would be a go or no go situation each time.We will see what we shall see.Respectfully:RTH

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Thanks DJ. I will check out your suggestions. I highly suspect that you are correct that there is some conflict between the data bases. The thing that really puzzles me is that some of the waypoints were tracked with no problem on some trials, and didn't at others. I would have thought it would be a go or no go situation each time.We will see what we shall see.Respectfully:RTH
It really does sound rather odd. Just for the heck of it, I generated a similar plan using FSB and got a route that approximated a great circle (but used tracks and fixes further north than yours) and contained 85 waypoints - ASV couldn't update the FS weather points with that many and just hung on me. I never got to the point of trying to load it all up in the plane, but do wonder if the plane can handle it...DJ

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Possible update:I may or may not have found the problem.I tried with nothing activated except FS9 (No ASA, FSC etc.) I got the same results. I was now consistently looseing autotracking and switching to a numbered heading when reaching the Swann waypoint, with ENO as the next waypoint. Indications changed to ENO as the next waypoint, but the autopilot would not play with that selection as the next destination on my route.I had already tried deleting the previous waypoints individually, with no difference, so I deleted both Annge and Swann with ENO as my first initial waypoint. With autotracking engaged (and indicating such in the autopilot), the bird ignored the activation and continued on the current heading.I then deleted ENO and manally re-entered it into the FMC flightplan. Tracking continued normally and there was no problem.In my original flightplan with FSC, I selected the "ENO VOR" as my waypoint. The FMC leg confirmed this as the frequency was displayed, however it would not track it. When I deleted/replaced this waypoint manually with the keyboard it was entered as an intersection, NOT a VOR and it solved the problem at least for this point in the flightplan..I strongly suspect that this is the case with all waypoint selections that result in this problem. Where multiple options (VOR, NDB, intersections, and/or fixes) are available, all of them may not be included in the FMC database, and if one is selected in the flightplan (with FSC, FSNav, etc.) and then imported into the FMC but is not included in the FMC Database, tracking does not know what to do and switches to the current heading. I just saw the exact same thing take place on the next progressive waypoint while I was typing this (RBV, which is also a VOR). Indications are that the FMC only recognizes waypoints, not VOR's. I will revise the flightplan in question to that format and see what happens.Time will tell:Respectfully:RTH

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Tried two long distance flights both ways.In FSC if VOR's are selected as waypoints and imported into the FMC, they are not recognized by the PSS 340-300 FMC/Autopilot, and it switches to a heading control. I imagine the same problem may occur regardless of how the flightplan is originated, however I did not check this out as the following appears to be the most simple solution (IMHO).If only intersections are selected for the same locations, autotracking seems to perform flawlessly.Happy flying:RTH

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