That characteristic GSM interference is actually quite harmless to most well designed systems. In some sense, the GSM buzz is more caused by bad design of the

That characteristic GSM interference is actually quite harmless to most well designed systems. In some sense, the GSM buzz is more caused by bad design of the audio amplifier than anything else. Also it's mostly caused by nearfield magnetic effects in contrast to RF emissions. I think it's safe to say that this is completely irrelevant to most avionics systems (but nobody is going to guarantee that).