Hi
To my knowledge, this is accurate. The engine cuts out because there is no fuel coming into the engine and because of that you don`t hear anything. RPM drops. It`s certainly not a bug, the game is meant to be like this.
I really believe that this is accurate because engine-sound is not the sound from the engine turning, but the mini-explosions (=burning fuel) in the engine... and that is what stops when you push your nose down...
I fear there is no fix to that, but if you want to, you can lower the realism-settings so that negative G`s don`t have an effect....
Sorry
