120-70B - Operational Authorization Process for use of Data Link Communication System

Date Issued
August 24, 2010
Responsible Office


This advisory circular (AC) presents various methods for operators of different data link systems to meet international standards set by the International Civil Aviation Organization (ICAO) and the regional airspace authorities. The Federal Aviation Administration (FAA) notes that there is presently no requirement in Title 14 of the Code of Federal Regulations (14 CFR) to have data link communications when operating in the National Airspace System (NAS). Instead, the regulations in 14 CFR govern radio communication systems, and nothing in this AC relieves an operator from the requirement to have and use a voice communication system when operating in international airspace or the NAS. However, operators that choose to operate in a reduced separation standard that requires the use of a data link system (in addition to the required voice communication system) must obtain FAA design approval and a revision to their 14 CFR part 121, 125, 125M, or 135 operation specifications (OpSpecs), part 91 subpart K (part 91K) management specifications (MSpecs) or part 91 letter of authorization (LOA), as applicable. The original AC 120-70 was applicable to Aeronautical Telecommunication Network (ATN), very high frequency (VHF) data link (VDL) Mode 2 communication systems. The Future Air Navigation System (FANS) 1/A system used in oceanic and remote airspace is an analog system which communicates over Aircraft Communications Addressing and Reporting System (ACARS). Guidance is needed for the operation of all systems and therefore the first revision AC 120-70A, was created.