First make sure your analog collective is set to the Slider+/- of your joystick accordingly.
- go to editor, place a helicopter, player as pilot
- raise Slider on joystick to maximum collective
- preview the mission
-> the engine and rotors will start but the chopper will not lift off
alternatively
- start the mission with player as helicopter pilot
- raise analog collective on your joystick Slider to maximum and fly to make sure it works accordingly
- crash the heli but do not touch the Slider, leave it at max
- restart the editor preview
-> heli will spin up the rotor but not lift off until you lower and raise the Slider completely