Go to config.lua, search and replace this:
-- Adds a audio sumbix while in a helicopter/plane (noise suppression) (NOTE: Get's applied to all helicopters/planes, not just the ones with a camera)
Config.UseSubmix = false
Config.NoSubmixInCamera = false -- Only applys if Config.UseSubmix is set to true, if true, this will stop the submix when you are using the camera
config.lua