Description / Abstract: This document contains Minimum Aviation System Performance Standards (MASPS) for communications utilizing High Frequency Data Link systems for the air-ground communications sub-network in an Aeronautical Telecommunications Network (ATN) environment. The FANS 1/A data link environment is also addressed. Where systems are global in nature, the system may have international applications that are taken into consideration. Compliance with these standards is recommended as one means of assuring that the system and each subsystem will perform its intended functions(s) satisfactorily.