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Many evolutions in the data link technologies and implementations required an update of the IFATCA (Controller to Pilot Data Link Communications (CPDLC) policy. Airlines growing use of VHF Data Link Mode 2 (VDL2) has offered a reliable sub network for CPDLC, Future Air Navigations System (FANS-1/A+) has removed the risk “out-of-date” messages and Aeronautical Telecommunications Network (ATN) Protected Mode CPDLC has eliminated the risk of “misdelivered” messages. But among other deficiencies to comply with ICAO ATN Standards and Recommended Practices (SARPs), FANS protocol is still vulnerable to this risk, eventually posing a safety threat in continental high density airspace when voice read-back is removed in a near future. Considering the lack of technical solutions to this FANS misdelivery risk, IFATCA opposes the use of CPDLC with FANS aircraft in continental airspace and requests ATN CPDLC only in high density airspace, and ultimately FANS replacement by ATN data link in oceanic airspace when ICAO ATN SARPs are upgraded.

IFATCA Policy is:

All implementations of CPDLC must demonstrate full compliance with ICAO ATN SARPs. However, in Oceanic and Remote Regions, where it can be demonstrated that CPDLC implementation improves controller pilot communications, it is recognized that non ATN compliant technologies may be deployed during a transitional phase.

The ICAO ATN SARPs and their progressive development form the definitive basis for any future CPDLC implementation.

In high density ATN CPDLC airspace, FANS aircraft shall be handled via voice R/T for safety reasons.

See: WP 96 – Istanbul 2007

See also: WP 92 – Buenos Aires 2003, WP 82 – Toulouse 1998 and WP 92 – Santiago 1999

IFATCA Policy is:

IFATCA supports efforts to define global safety and performance requirements for data link services in order to:

  • achieve harmonization;
  • support further implementation to improve safety and efficiency.

See: Resolution B1 – WP 85 – Accra 2018


Last Update: September 29, 2020  

November 5, 2019   220   Jean-Francois Lepage    COM    

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