well, on a western airfield, you can tell when an IL-76 or TU-154 is coming in. Everything stops for a second as a "whomigod it's the apocalypse" sensation ripples through, followed by, "it's only a 727ski" or whatever. Those things are loud as the end of the word. Now, could you tell the difference between an Air Kazakh and an Azerbaijani liner by the difference in sound between 2 and 4 missing turbine blades?