Seems lately when I use any of the PSS aircraft the sound turns off after a short time, most notably the air traffic control. Anyone know what causes this? thanks

Ther have been reports of this before. Make sure before flying the PSS aircraft you start with a default aircraft and have the battery and avionics on. Something in the way they are developed causes the battery to go dead even if you have FSUIPC.

it is very important when using PSS aircraft to load a default aircraft first. before switching to the PSS aircraft of choice confirm, as stated by the prior poster, the battery and avionics are in the 'on' position.(i state the above based upon experience using PSS's dash8, A32X, A330 and A340 products since FS8).