llation of dual TOR-94D ATC/MODE-S/ADS•B Transponders Sikorsky S-76C INTRODUCTION GENERAL This Rotorcraft Flight Manual Supplement describes dual TDR-94D ATC/Mode- S/ADS-B transponder(s) with dual RTU-4200. The RTU-4200 is capable of providing Flight ID information to the Mode S transponder system(s) for