The pilot seats of helicopters within the game are too loud, preventing voice chat or VON usage while flying.
To resolve this, I reduce my Audio Effects to less than 10%, from somewhere around 80%. However, this might affect those listening for enemy foot steps, or other sound indicators?
(This bug mainly effects pilots, as those within the passenger compartment of the Mohawk are subjected to less rotor noise than the pilots. This later issue concerning equality of noise DB levels may have been recently fixed on 27 Sep 2013.)