If you own a heli & have the key in your toolbelt, you can set it up as an evac chopper, to do this, just look at your heli and scroll down & select SET EVAC CHOPPER. your heli should be locked when you set it.

Now, if you are over 500m away from your heli, you can call it to your position, to do this just right click on the radio in your toolbelt.

A check will be made & provided the heli is on the helirescue pad, is not too damaged and has fuel, it will fly to you, you will get a pop up box telling you the hight, flight speed and distance the heli is from you.

When it arrives, the pilot will check that you are the owner (By player ID) and unlock the heli for you to use it, You do not need the key to call your evac chopper, you can call it from fresh spawn as long as you have a radio.

For some reason, the server does not record some players ID's, this means after you log, the evac pad will no longer be registered and will not work, there is nothing I can do about this, it will either work for you or it won't, it does not work work me.