I have seen numerous posts over time where it is suggested that an air file is not up to scratch and people suggest substituting it with one of the MS default air files.Could someone please explain in simple terms how I go about this and what needs to be amended to make the transition work.TIA

Sometimes swapping airfiles work; sometimes it doesn't work. Just have to try. It really simple. Just open up the aircraft folder and rename the original airfile to ****_orig and then pick the airfile you want to use and rename it. That's it. If you want to go back, you have the backup copy.

FS2002 does things differently than previous MSFSs. It uses both the *.air and aircraft.cfg files for aerodynamic and other data. While FS2000 did some of this, FS2002 does a great deal more. For instance, if you import an FS98/FS2000 aircraft into FS2002, FS2002 will read the *.air file, upon initial selection of this aircraft, and write new entries into the aircraft.cfg and *.air file. These changes may or may not help the aerodynamics of the imported aircraft. Once FS2002 has modified the above files, the data in the aircraft.cfg file takes precedence over the data in the *.air file.So! Where does this lead? If you take just the *.air file from a comparable aircraft, i.e., 737, A300, and substitute it for the *.air file of another aircraft, it may or may not work correctly. The reason is the *.air file and aircraft.cfg file are not matched. You may have to make adjustments in the aircraft.cfg file to compensate for the new *.air file, such as, the aircraft is sunk into the runway or is floating above the runway.Well! How about if you substitute both the *.air file and aircraft.cfg file? May or may not have problems as above. You still might need to adjust things in the aircraft.cfg file.I won't even get into the necessity of making adjustments in the *.air file since this was problably the reason you wanted to substitute the *.air file anyway!If you do make substitutions, it is going to be a hit or miss proposition and you will probably need to make some adjustments.

Very well said William!Regards,-John