Originally Posted by IO540
I do wonder what the point of this verification is, because I could be legally flying under the LTMA at 2400ft, non-radio, with a transponder returning FL150, causing everybody to !!!!! themselves, but they have no means of checking because they don't know who (if anybody) he is talking to.
Having had Transponders outside of tolerance it is a necessary requirement if you're going to use that data from an ATC point of view.
And believe me - if the 2400ft / FL150 occurence happened you probably would find someone knocking on your door
but then my transponder (both KT76C and the later GTX330) permanently display the FL being returned on the LCD display. Doesn't almost every Mode C unit do that?
No - mode 'C' transponders that do that are actually in the minority. It's more available on more modern mode 'C' & 'S' units