There’s no requirement. The issue is if you get down to a low ground speed in flight the transponder might go into the ground mode. I think it’s getting a little overblown on RAS. Trig recommends a squat switch to compensate for it. Some of the other transponder manufactures can compensate for it by programming. I haven’t put a squat switch in any of the power airplanes I’ve installed ADS-B transponders in.