At AA, Sim Pilots and ground school instructors are non line pilots. They may have never flown at an airline or even be pilots. Some are retired pilots of some kind - either military or commercial, and some are Boom operators or Loadmasters for example.

Check Airmen do the sim check rides and final training rides and give IOE. You have to be a Captain (line pilot on seniority list) to be an instructor (Check Airman) other than the Sim-Ps and ground school instructors. We have a very few instances where some furloughees have been hired as Sim Ps - very few.

This is very different than many airlines. If you are an FO of any kind you do not get the opportunity no matter what your experience is.