Previous helicopter sound mods replaced the blades sound files. These files are split in milliseconds and played randomly, which makes modding very difficult. I decided to replace the engine sound files (which are loops that last for a second), crank the volume up, and silence the blades sound. It worked out quite well, at the cost of having a very tedious installation and maintenance.
Features
Replaces every helicopter sounds (including Avenger) with more realistic sounds.
Bugs
Blade sounds will be super loud when you are changing a radio station
Installation
You have to replace every sound data files which defines the sound of the helicopter. Detailed instructions are included in the .zip.
Credits:
SilkWitch