This script provides working helicam which has 3 different modes (normal, thermal, night vision), plate recognition system and zoom feature. I have used this script on my own server and never experienced an issue but since I have extracted it from my own gamemode, if you come across a issue, post a comment below, I will try to fix things.
Right Mouse Button: Changes mode (normal, thermal, night vision)
Space: Locks to a vehicle and shows its plate and model.
Put the files you downloaded in their respective places
Add require('helicam') to client_packages/index.js
Call "enablehelicam" event from serverside or via keydown event.
davwheat - FiveM version of this script.