While in external view centered, the aircraft sound is too low, almost you can't heard it but if you turn the view the sound grows to normal.
I tried today with the normal beta 0.70 and the develop version 0.71
I try to look in other post but none reproduce the same problem I have.
This issue is also checked in multiplayer and solo and even ask the people in the server/game about that but they told me that didn't notice at all(but I don't know if they understand my inquiry)
In internal view sound is ok.