July 19, 2019
A recent North Atlantic (NAT) Operations Bulletin provides flight planning and operational guidance to operators preparing for the final phase of the Data Link Mandate (DLM) that expands the vertical limits of the ICAO NAT region from Flight Level 290 to FL 410, inclusive, effective Jan. 30, 2020.
After this date, aircraft lacking the required equipment can request climbs and descents through DLM airspace, but ATC will consider them on the tactical situation of the airspace at the time of the request. The bulletin made clear that “such flights may not receive an ATC clearance, which fully corresponds to the requested flight profile.”
According to the bulletin, effective Feb. 7, 2013, “all aircraft on or at any point along two specified tracks within the NAT organized track system (OTS) between FL 360 and FL 390 inclusive” were required to use controller-pilot data link communication (CPDLC) and automated dependent surveillance-contract (ADS-C) equipment. In addition to tracking aircraft conformance to the cleared route and flight level, ADS-C benefits search and rescue, if needed.
With three steps, Phase 2A began Feb. 5, 2015, expanding DLM horizontally to all NAT tracks from FL 350 to FL 390. Phase 2B, effective Feb. 5, 2017, expanded DLM requirements at these flight levels throughout the ICAO NAT region. With this latest revision, Phase 2C will complete DLM’s vertical coverage by establishing a ceiling at FL 410.
DLM does not include airspace north of 80° North, where geostationary satellite coverage makes CPDLC service less reliable. Nor does it include the New York Oceanic East flight information region, or airspace where ATC tracks aircraft with radar and ADS-B coupled with voice communication. The bulletin graphically depicts the coverage areas and includes operational guidance for failure of required equipment.
The mandate’s goal is to have 95 percent of NAT aircraft equipped with future air navigation systems 1/A, ADS-C, and CPDLC by 2020. The objective is to enhance communication, surveillance, and ATC’s NAT “intervention capabilities” to reduce collision risk and to attain the target safety level, “particularly on the vertical plane.”