After system-changing (Windows8==>Windows 10Pro) and newinstall. FSX+Acc some aircrafts appear only as fragment =>pic. ..itis an addon-citation, but same bugs comes by default H101-heli. Sure I tried "compatiblity--win8"---no way. What can be reason?
I would check and make sure you did not update to the beta version I have FSX:STEAM edition and when I tried using add on aircraft with the beta branch add on aircraft would do exactly what you describe or worse yet be grey in color with zero animations!
Once more thinking over all again---logical I hope--: Near ALL aircrafts work well, only few not---so not Windows or FSX general is reason, but any aircraft-files---which difference exactly isn't easy to find--....so what.