This is an Arma 3 Eden editor tutorial on how to repair a helicopter and refill it's ammo and fuel from a helipad.
EDIT: Don't forget to make the trigger repeatable (forgot to mention that in the video).
Copy & paste the following into trigger activation:
{_x setdammage 0} Foreach thislist; {_x setfuel 1} Foreach thislist; {_x setVehicleAmmo 1} Foreach thislist;