How to make helicopter fall and explosion

How am i going to make my helicopter fall as my helicopter is now depending on Rigidbody to fly. my helicopter contains many smaller parts like mainbody, roter, camera so on. and some parts is attached with OnTriggerEnter explosion script. The helicopter is attached with OnCollisonEnter explosion script. So now i have to make it fall and Collision on the terrain to explode. So any1 knows how to make my helicopter fall please help me thx. as i am using another HUB script to tell my helicopter to fall in if(helicoper no fuel) fall.

My Rigidbody

Mass : 1276

Drag : 0.1

Angular Drag : 1.5

Use Gravity : Check

Is Kinematic : Uncheck

This should give you a good idea. It is one of the few unity Helicopter tutorials. If the rotors hit any collider they will explode and send the helicopter crashing to the ground. Good luck :)