Yesterday guys shot the heli and it disappeared after shotdown. There wasnt even fire.
But on the map there was the marker for heli shotdown.
I don't know if this is plugin or Rust related.

I am having the heli just vanish mid flight lately. Not sure what the issue is.

This was discussed in an other thread.
This is was Shady said and it worked for me:

I believe this is the intended behavior in default Rust. You can adjust how long it takes before it starts it's "leaving process" by changing the Heli's life time. "Maximum helicopter life time in minutes" should be the config option. Try changing this to a higher value and see if it helps your issue.

Cheers. I'll try changing that and see what happens.