Why the Viavi IFR6000 and IFR4000 Remain Industry Standards for Transponder and NAV/COMM Testing 18 December 2025 AvionTEq Blog Discover why the Viavi IFR6000 and IFR4000 remain industry-leading avionics test sets for transponder, ADS-B, NAV/COMM testing. Read More. [More] Share