There's something else going on? As Boof said, nobody else had a issue with the Fireboss. Including me
This is from the G3.5 board but it still rings true:
HOW DO I INSTALL CUSTOM CONTENT?
A. When you have downloaded the file you want from our swap site, load RealFlight. Select the "Simulation > Import > G3X" menu item in G3.5 or "Simulation > Import > RealFlight Archive" in G4 and G4.5. In the import dialog box that appears, locate the file you downloaded and open it. RealFlight will import the file. In G4 and G4.5 you can select more than one file to import at one time.
Do not attempt to put custom content in RealFlight's data or documents folders; this will not work.
Q. HOW DO I REMOVE CUSTOM CONTENT?
A. Go to the "Simulation > Manage User Files" menu item. There you will see a directory-like structure to see all of your custom content. You must ALWAYS use the Manage User Files dialog to remove custom content; attempting to remove any files in RealFlight's data folders will cause problems.
Q. WHY DOESN'T THE AIRCRAFT I JUST DOWNLOADED LOAD?
A. You probably downloaded an Aircraft Variant for which you don't have the original model. Every Aircraft Variant description page gives the name of the Aircraft Model that it requires. Most of these are based on aircraft that are included in RealFlight or in its Add-Ons or Expansion Packs. Some Aircraft Variants are based on Aircraft Models that are available from the swap pages; if this is the case, the Aircraft Variant description page will include a link to the Aircraft Model file that it is based on.
Q. WHAT IS THE DIFFERENCE BETWEEN AN AIRCRAFT MODEL AND AN AIRCRAFT VARIANT?
A. An Aircraft Model includes a 3D model that RealFlight uses to display an aircraft on the screen. Aircraft Variants only store changes to the physics properties of an aircraft such as its weight and the size of its motor. Since the Aircraft Variant file does not include a 3D model of the aircraft, RealFlight will not be able to display the aircraft on the screen unless the Aircraft Model on which the Aircraft Variant is based is also present.