Originally Posted by PerfInit
AM is very succeptible to interference. New and better technology has been available for quite some time (20+ years). Why the aviation industry continues to "ancestor worship" is beyond me.
Because in order to shift you would need an entirely new frequency band, at least temporarily during the transition. You can't use amp mod on the same freq at the same time as other encoding techniques. Of just cut everybody over at 0200 on a Sunday.
Also airlines, NBAA, and AOPA don't want to buy new radios (that would probably cost twice as much as a 152).