Data link applications are being implemented in flight operations utilizing FANS-1/A (which includes CPDLC and Automatic Dependent Surveillance-Contract (ADS-C). Data link applications operate without any specific knowledge by the user as to whether a satellite, VHF, (VDL M0/A or VDL M2) or HF data link (HFDL) sub-network service is in use. However, these applications may be limited by the level of end-to-end data link service implementation in use (e.g., ACARS, FANS-1/A ARINC 622).

The different systems include ATN-Baseline 1, a digital system and FANS-1A, which is basically an analog based system. At the present time the digital operation is known as VDL-Mode 2 system. The analog operation is known as the VDL-Mode 0/A. The FANS 1/A system uses both digital and analog components.

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). 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.

Type of Operation Guidance Materials Overview Presentations Approval Mechanism Additional Information
Data Comm AC-120-70

AC-91-70A

AC-20-140A
CNS (SWF) OPSPEC/MSPEC/LOA A056 GOLD (Global Operational Data Link Document)

Asia Pacific Operational Authorization Information Package (PDF)

NAT Resource Guide (PDF)

Pacific Resource Guide (PDF)

Job Aid (Draft) (PDF)

Data Communications (Data Comm)