TGEA Helicopter

So, I took a peek at the helicopter resource:
http://www.garagegames.com/community/resource/view/9263/9#comments

and saw that someone was able to get it into TGEA without too much of a hastle, so I tried it myself, made code adjustments and it compiled, however I'm getting a very annoying issue.

I can spawn and delete the helicopter perfectly fine (model is showing fine), but over half the time it spawns under the map, and then the one time I placed it above the map, it fell to the ground, and on collision with the ground, my game crashed.

I'm just wondering why this would happen.

Implemented .cpp/.h files here.
http://www.phantomdev.net/staff/phantom139/public/heli.zip

NOTE: I just loaded the helicopter code (.cpp/.h, .cs) in and added mJettingDN to vehicle.h in my game's project.