Ok guys, here's what i did..
In the aircraft.cfg file, under the turbine engine section, i changed the air intake size from 1.0 to 4.4. 1.0 is about the size of a human head so it was way too small..
Next, i took the plane for a spin at 20700 feet and ran it through afsd ( image below ).
The speeds everyone is seeing at 20000 feet are correct and normal..
As you cimb up to 20000 feet, the FADEC is purposely decreasing the N1 ( LP spool ) rpm to allow for there being less air. As you can see in the pic, N2 ( hp spool ) remains at 100%. The speed you are seeing in the EADI is derived from the air pressure as it hits the pitot tube. since there is less air at 20000 feet than sea level, its not getting enough air pressure to read the true air speed of the plane. as you can see below, the true airspeed is still above 350 knots. This is working as it should be..
If you folks would make that littler change in the aircraft.cfg file using notepad or win-vi, you should be fine..
The change will also be reflected in the next update on the flight model, but my intentions are to get you folks up and flying and having fun as quickly as possible without having to wait for me. so what i'm gonna do is let you all know what changes i'm making in the aircraft.cfg file so that you can change them too, and be flying better, that much quicker..