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mgh

Urban myth...

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BillI'll take up your offer in another thread to explain why it becomes necessary to load a default aircraft before some complex aircraft. If I came over as confrontational that was because no one would/could demonstrate why it is necessary and what is the underlying mechanism. Over to you ;)

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Sorry, but I don't think your post is helpful.I have no axe to grind either with AVSIM or developers. I am simply seeing a reasoned explanation. My frustration probably began to show in the earlier thread as result of replies that basicaly said "these are complex models and the default flight has to be loaded first to allow them to run." This may wll be true but doesn't answer the question why?. I hope in the calmer atmosphere of this forum I may get an answer.

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I've read your question, but will have to beg off an in depth reply for the nonce, as we've just released the Liberty XL2 and I'm very busy at the moment. :-cool Hopefully, Doug will chime in on this, along with Jean-Luc and a few other developers. There are some very real underlying reasons why many of the more complex releases require that the default flight be unchanged from the "out of the box" state, even if not requiring that it be loaded first.Even without diving into the matter too deeply however, one thing that comes to mind immediately is that, folks can save some very bizzare combinations of states, whether on purpose or by accident (i.e., corrupted file(s), etc.) So, having a guaranteed, clean baseline default flight file to "reset things properly" is always a good starting point for diagnosis. In fact, more often than not, it is the "cure."I will however return to this thread ASAP, as it would be helpful to flog on the details here, where the signal-to-noise ratio is much lower... ;)

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Both have thousands of hours of real experience of real aircraft, but both know almost nothing about the inner workings of FS9 Yep, That gets the head of the nail

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Thank you for the indepth treatise... Hopefully it will be read and understood... ;)

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FSAviatorWell said mate :) Im thinking of cut and pasting this into every project I send out form now on......but then again who reads the read me Wozza

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Thanks for your explanation that if a flight is saved, say, with an iced aircraft (IceAccum not equal to zero?) then it will be iced when the saved flight's re-opened, iced if another aircraft's simply loaded, and also iced if the airport is changed. I understand this to be a logical consequence the way Flight Simulator stores flight details in .FLT files.But (and there's always a but) it doesn't explain why, if the sequence is open Flight Simulator and then create a new flight, it becomes necessary to load the default flight. What saved flight is involved? Similarly, it doesn't explain why it is necessary to load a default flight before re-loading a saved flight with a complex aircraft. Where is the erroneous/random data coming from in these cases? What is meant by the "default flight"? Is it the user created DEFAULT.FLT file in C:Documents and SettingsUserMy FoldersFlight Simulator Files which could be in any state, or FLTSIM.FLT in C:Program FilesMicrosoft GamesFlight Simulator 9Flightsother, or even MEIGS.FLT in the latter folder?

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The "default flight" is the file ...FlightsotherFLTSIM.FLTIt is used as a "template" during "Create A Flight" routine used in the UI, and provides the "baseline" for everything except for those options chosen in the UI, such as Departure Airport, parking/runway, time of day, and date.Open FLTSIM.FLT in Wordpad and look at all the information that is stored. Note that all possible states are described, and that they are set to either ON/OFF states, or "reasonably expected numbers."Now, open the ...Flight Simulator FilesPrevious flight.FLT file and compare those entries, with the FLTSIM.FLT file using side-by-side Wordpad windows...The "Previous flight.FLT" file is the one created whenever you quit FS9 and it saves the information based on the last a/c you had loaded, and saves all the current state data, including a lot of information that is specific to that particular aircraft!Using the "Previous flight.FLT" as the "baseline" for another, more complex aircraft such as one of the Level D or PMDG offerings, will most likely result in some erroneous state data being used when the panel system is loaded. If the aircraft's gauge system is programmed to use "base line data only" as part of the initialization process, then it should be obvious that because the "Previous flight.FLT" file contains non-baseline state data, there is a distinct possibility that some necessary initialization routines might fail (best case), or the "not-expected data" might engender a complete crash of the panel initialization (worst case), with the typical errors being "ntdll.dll," "gdiplus.dll," "panels.dll," or any one of a dozen other "xxx.dll" files that might be used by the aircraft's gauges as dependencies.Now, suppose that the simmer has exited FS9, and decided to make their own favorite aircraft, at a specific airport, etc. the "default flight!" Now, the baseline state is set specificially for that one aircraft, and it is quite possible that - because of the changed "baseline" state data being unique to this aircraft - attempting to load another aircraft using this saved state data might well result in the same problems encountered in the example above, for the very same reasons!As a programmer of semi-advanced, integrated panel gauge systems, I try to anticipate as many of the truly "goofy" data states that a user might leave behind when quitting the sim, or changing the default flight configuration, but there are just so many that it's well nigh impossible to anticipate all of the possible combinations!It is for these reasons that we ask folks to please try loading the "real" default flight whenever they run into a "problem," before running to the forum screaming "Your crappy model crashes my system!" :)It is useless to cry "foul" until it is verified that the unexpected behavior persists whenever a clean, know-to-be-valid, default flight is loaded first. If the "problem" persists after a "clean load of FS9 to the original default flight," then there possibly is a "bug" that will need to be found and fixed, although even then there remain plethora other reasons why the problem occurs, such as overheating, video driver issues, and ten-dozen other hardware/software problems that might exist... ;)In short then, using a known-to-be-valid FLTSIM.FLT file is an excellent diagnostic tool, and - in 99.9% of the cases - proves to be the "cure" to user's issues.

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I have no problems with the the fact that using a saved flight for one aircraft with another or selecting another aircraft with ALTAircraftSelect Aircraft. can give problems. Changing from a 747 cruising at altitude to the Wright Flyer is likely to cause problems even though they are both default aircraft.However to return to my previous point relating to using Create a Flight, is it necessary to load the default flight first? It seems to be agreed that Flight Simulator uses the FLTSIM.FLT when creating a new flight so why would there be an advantage in loading the default flight first? Similarly, if a previously saved flight is loaded what is the advantage in loading the default flight first? The values in the .FLT file should be valid - after all they were generated by the same aircraft.

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>However to return to my previous point relating to using>Create a Flight, is it necessary to load the default flight>first? It seems to be agreed that Flight Simulator uses the>FLTSIM.FLT when creating a new flight so why would there be an>advantage in loading the default flight first? Similarly, if a>previously saved flight is loaded what is the advantage in>loading the default flight first? The values in the .FLT file>should be valid - after all they were generated by the same>aircraft.The key point is that the "default flight" - the FLTSIM.FLT file - should not ever be modified...When using the "Create a Flight" option, the new aircraft is loaded to the sim using the settings in the FLTSIM.FLT file.Only sometimes (read: rarely!) is it necessary to actually LOAD the default flight prior to loading another aircraft, and that is done only as a last resort to "clear the decks" so to speak and reset everything in the sim back to the default state.Saved .FLT files aren't immune to 'bit twiddling' and 'corruption' either... In fact saving anything to file from FS is prone to problems, just observe how often people's LOGBOOK entry in FS9.cfg gets corrupted! :)I honestly don't know how to make it more clear than this... ;)

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The same issue is approached a little differently over at HoverControl. Instructions to the user are to start the provided baseline flight, move to your favorite airport and time, and re-save immediately.This saves the state that the developer intended, at the place the user likes to fly out of a lot.One thing developers know that I haven't seen mentioned specifically goes a little beyond the "unexpected results of random bits" when a flight is started. If your default flight does not have spoilers set to a state and AC A doesn't have spoilers, then you load AC B which does, what state are the spoilers in when you spawn?Toss a coin... you could be right half the time.Jordan Moore's 412 carries huge warnings about this because starting a 412 flight from the create a flight menu rather than a saved 412 flight almost invariably results in the generators being frozen in the off state. That's not a good thing when your battery power runs out about 5 minutes into the flight.Some aircraft have extremely complex initialization routines that have to be followed precicely... such as the Dodosim Advanced 206. Now there's an AC that not only has to be started from a saved flight, it has to be started COLD from a saved flight! Otherwise, you could get some really strange things happening when you engage the advanced flight dynamics.Many of these AC contain custom gauges, features and variables that are not seen elsewhere... yet have to be initialized properly in order to work. This is why the developer took the time to create a flight to start from, to ensure that all those factors were taken into account and taken care of.Just start from that flight, or the default flight if the developer instructed to do so, and resave as another flight after you move to your usual area. You can make submenus of flights to keep it all organized if you want to.The point is that for a complex AC to work properly, you need to start it off in a known valid state. After all, you don't go start your car in the morning with the temp gauge already pegging 250 degrees F, do you?Scott / Vorlin

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