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United States Department of TransportationUnited States Department of Transportation

Flight Operations Group

Data Communications (DataComm)

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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.

DataComm guidance materials
Type of Operation Guidance Materials Approval Mechanism Additional Information
Data Comm

AC 90-117

AC 91-70B

AC 20-140C

OPSPEC/MSPEC/LOA A056

NAT Resource Guide (PDF)

Pacific Resource Guide (PDF)

CPDLC-DCL Site Implementation (PDF)

NAS Data Comm Guide (PDF)

Performance-based Communication and Surveillance (PBCS) Monitoring

Alternate VDL A/0 Compliance (PDF)

Data Link Communication Compliance Guide (PDF)

Single European Sky Initiative and Data Link Services (PDF)

Temporary NAT DLM Suspension (PDF)

Data Link Problem Reporting and Charter Enrollment (PDF)

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