Avenger rotor blade problem

[NCHK]

Hi, I'm new to GTA V modding. I edited my avenger helicopter model to incorporate some additional functionality to it. After exporting, everything is working as intended. The problem is with the rotor blades. In GTA V, every helicopter has two rotor blade textures. One for fast spinning and the other for slow spinning. But they both won't be visible simultaneously. After the modifications to the model, both rotor blade textures were visible simultaneously. Also, when the rotor blade hits on something, the game crashes. Does anybody know how to fix it? My Zmodeler trial will be over soon. If someone knows about this problem, please reply immediately.