Troubleshooting AI Flight Planning Difficulties

AI flight planning is a form of scenery design. Whether you use Microsoft’s Traffic Toolbox, which ships as part of both FS9 and FSX, or a TTools compatible utility (e.g., TTools itself, AIFPC or AI Flight Planner), successful AI flight planning requires some knowledge of the “innards” of FS9 and/or FSX, as applicable, and well as an understanding of flight plan data.

For TTools-compatible flight planning, there is no better explanation of flight plan data than the “Source Files and Formats” section of the TTools user manual. However, there is no comprehensive source of information on the inner-workings of FS9 and FSX. While most problems you’ll encounter have been discussed, probably numerous times, in various forums, finding that information can be a tedious and trying experience.

The purpose of this document, then, is to provide a checklist of things related to FS9 and/or FSX to look for when your flight plans don’t work.

Traffic Analyzers - In diagnosing AI difficulties, a tool such as Traffic Toolbox Explorer (part of Traffic Toolbox but useful for all flight plans) or one of the freeware AI traffic utilities (such as Peter van der Veen’s Traffic Analyser) can save you a great deal of time by telling you whether or not a given AI flight plan is being processed by flightsim. (If flightsim isn’t processing the flight plan or leg of interest, there’s no point wasting time “sitting” at an airport waiting for the flight to arrive!) Instructions for installation of Traffic Toolbox Explorer are contained in the relevant SDK. (For FSX, you must own the deluxe version to have access to the SDK.)

Converting Prepared FS9 Traffic Files for Use with FSX – With the ready availability of prepared flight plans covering airline system-wide schedules, the vast majority of AI difficulties reported with AI Flight Planner are related to conversions.

There are three steps in converting compiled-for-FS9 AI for use with FSX:

• convert the traffic file – this can be done individually or in bulk using AI Flight Planner; converted traffic files may be saved to either FSX’s Scenery\World\Scenery folder or to any other scenery folder enabled in the Scenery Library.
• install the required aircraft in the FSX\SimObjects\Airplanes folder (or other folder designated in the FSX.cfg file, and
• replace propeller textures as necessary.

A detailed procedure for converting MAIW FS9 packages for use with FSX can be found at The Owls Nest (http://www.interkultur.de/gossmann/fsx/maiw.php). This procedure may also be helpful for packages from other sources.

Please note that FS9 flight plans in text (TTools) format do not need conversion.

Don’t Mix FS9 and FSX Traffic Files - The most frequent cause of AI difficulties with FSX is the mixing of compiled-for-FS9 and compiled-for-FSX traffic files following conversion. At time of writing, most prepared flight plan data, e.g., WoAI, MAIW, is compiled for FS9. You can load these traffic file directly into FSX and they will (or should) work. But, if you place a compiled-for-FS9 traffic file in the “purview” of FSX, any compiled-for-FSX traffic will disappear. All traffic files in FSX must be compiled for the same target flightsim version. They must be either all FS9 traffic files (in which case, if you want default traffic you must use the FS9 default traffic file or convert the FSX default traffic file for FS9) or all FSX traffic files. AI Flight Planner will help you locate compiled-for-FS9 traffic files. But, only you can ensure there’s no mixing. Please note that there is no requirement that traffic files be named traffic …bgl. While that naming is customary, it is not a requirement.

Prerequisites for an AI Flight Plan – There are only three basic ingredients needed for proper AI operation:

• a valid flight plan whose legs are scheduled so as to be achievable with the specified aircraft;
• adequate parking at the destination airports properly connected to the runways – adequate for the number and types of AI aircraft that may exist at the airport at any point in time plus the user aircraft, and
• a compatible aircraft with an aircraft.cfg file that designates the aircraft (title) as an AI aircraft (i.e., the aircraft.cfg file contains a corresponding “[fltsim.nn]” section).

AI Flight Planner will warn you if, based on the cruise speed of the designated aircraft, a flight plan leg cannot be completed prior to departure time of the next leg in sequence, and of a host of other flight plan errors. However, AI Flight Planner cannot ensure that adequate parking is available. (Note that, for FS9, flightsim assigns parking based on model radius; for FSX, the wingspan specified in the aircraft.cfg file is used.) Nor will it warn you automatically if a required aircraft does not exist on your system. But, you can ask it to check at any time using the Aircraft / Check for Missing Aircraft menu item.

Troubleshooting a Traffic File - If a file compiles or re-compiles without error using AI Flight Planner, it is highly unlikely that the traffic file is invalid. It may not work on your system but, if not, the problem almost certainly lies with the flight planning data.

The first step in troubleshooting a traffic file is to isolate that file. All other traffic files within the purview of the target flightsim version should be disabled. As well, it may be helpful to disable all add-on scenery except those required to generate the airport(s) of interest. For the default traffic file and any others in the \Scenery\World\Scenery folder, this means either changing their file extension to something other than “.bgl”, such as by appending “.xxx” to the file name/extension, or temporarily moving them to another folder outside the purview of the target version of flightsim.

If the problem no longer exists once the traffic file of concern is isolated, you can determine the real source of the problem by re-enabling the other files (one-by-one or in a binary fashion) until the problem recurs. If isolating the traffic file doesn’t help, then check the following. (If you’re using FSX, it is assumed you’ve already removed any FS9 files.)

Symptom	Possible Causes
AI do not materialize for departure	· No/inadequate parking · No/invalid aircraft
AI do not materialize for landing	· No/invalid aircraft · 37- minute problem (“raw” compile mode only) – see AI Flight Planner User Manual
AI executes missed approaches	· User aircraft on runway · No parking available for a/c
AI lands but disappears after exiting runway	No taxi path to assigned parking spot
AI does no proceed to runway for takeoff	No taxi path to active runway

Unfortunately, flightsim does not warn you about missing or invalid aircraft. It simply ignores any flight plans for that aircraft. But, you may identify missing aircraft by loading the traffic file into AI Flight Planner and running the Aircraft/Check for Missing Aircraft function.

If a missing or invalid aircraft is indicated, ensure that the aircraft title is declared as an AI aircraft in the relevant aircraft folder. If it isn’t, update the aircraft.cfg file and try again. If it is, replace the missing/invalid aircraft in the aircraft List with a default aircraft or another aircraft you are certain will work. (Not all aircraft you download will perform satisfactorily as AI aircraft, particularly with FSX. Default aircraft are reliable alternatives.) If prepared flight plan data has been used for the faulty traffic file, you should also check whether or not the cruise speed has been altered – even if it’s a default aircraft. If it has, try restoring its normal cruise speed.

If inadequate parking or missing/broken taxi paths are suspected, you should analyse the “afcad” for the destination airport using AFCAD 2.21 (FS9 only), ADE (FSX only) or AFX (payware, both) or other airport editor. They all have fault-finders to help you identify and resolve such problems.

Summary – It’s tempting to download the system-wide flight plans for your favourite airline or a package that will populate your local military airfield. But, it’s frustrating when you attempt to convert those packages for FSX and they don’t work. Hopefully, the foregoing will help you avoid some of those problems or, if you experience them, help you to correct them. Be methodical. Most important, don’t get discouraged. Once you find the cause, you find the AI generated very satisfying. And you’ll probably learn something along the way.

If all else fails, take a tip from bobbyjack, a frequent contributor to the AI Flight Planner forum. Set your system-wide flight plan aside and create a simple two leg flight plan to test the various aspects of your system that seem not to be working.