i am test flying the MIG-21 bison and i have a setting for setting the brightness for the HMD (alt+L and scroll to change) but when i click alt+L i hear a sound (high tone beep, beep(a bit higher tone), beep(highest tone of them two)) and when i click alt+L again i hear a sound (triple low tone sound). I thought it was just my program on my device but its only in-game. Does anyone know what that sound represents?