If you are planning to have all of the PMDG aircraft installed on flightsim 2004 (aka 9), the procedures are as follows:
- Install the PMDG 737 FIRST with every possible patch/service pack upgrade etc.

- Install either the PMDG 747 or the PMDG MD11, followed by the other (the order in which you install these next two planes does not make a difference and/or create any installation problems)
- Install the latest AIRAC database for the PMDG's

Note: It is imperative that you install the PMDG 737 with all the patches BEFORE installing the other PMDG aircraft. If this is not done, the 737 installation will corrupt the other files from the other PMDG aircraft. In such a case, the 737 installation will either corrupt flightsim to the point of no launching

; you will not be able to select any of the PMDG aircraft for flying and/or selecting those aircraft will cause flightsim to crash

. One of your options at such a point is to uninstall all of the PMDG aircraft that you had installed

(the 737 requires a special uninstall tool, which can be found here:
http://www.precisionmanuals.com/file_library/misc/PMDG_737_REMOVE.EXE) and then reinstall the PMDG aircraft in the correct order, starting from the 737; the second, and worst option, is to reinstall the whole of flightsim

.
Happy flying
