VHF Digital Link Mode 2 (VDLM2)

Data link technology is now the standard in routine communications between flight crews and air traffic service providers. In addition, flight-operations applications—such as graphical weather descriptions, electronic charts, and engine/aircraft health monitoring programs—are commonly used to enhance flight efficiency and safety. Both of these factors have precipitated a strong need for far greater digital bandwidth from what has been historically provided by the character-oriented Aircraft Communications Addressing and Reporting System (ACARS^®) technology.

In response to the additional bandwidth that these technologies require, ARINC developed VHF Digital Link Mode 2, or VDLM2, a bit-oriented, air/ground and ground/ground data link technology that delivers information at 31.5 kbps—over 10 times the rate used by ACARS^®.

Aside from its much greater bandwidth, VDLM2 offers other significant advantages over ACARS^®. It is based on ICAO standards and recommended practices (SARPs) and allows for a distributed architecture with future-proof growth potential. VDLM2 is currently the only technology that is compliant with ICAO Aeronautical Telecommunication Network (ATN) requirements.

VDLM2's expanded bandwidth has allowed ARINC to offer a whole new range of flight information, aeronautical operational control, and air traffic control applications and services.

ARINC has always been a leader in aviation communications and its involvement with ATN and VDLM2 dates from the 1990’s when the ICAO ATN SARPs were being developed. In year 2000 ARINC was the first company to deploy a VDLM2-capable ground station and operationally demonstrated its use for ACARS over AVLC (AOA) communications. Since then ARINC has focused on validating VDLM2 as a next-generation ATN-compliant Air Traffic Control (ATC) data link service and expanding the coverage footprint. Today ARINC operates a network of over 380 VDLM2 ground stations, deployed in USA, Canada, Europe, Middle East and Asia, supporting more than 2,300 commercial VDL aircraft and 200 military aircraft for a total of more than 5.5 Million VDL messages each month. This includes a high-availability VDLM2/ATN network deployed as part of the Eurocontrol Link2000+ programme and supporting the majority of ATN/CPDLC flights in Maastricht airspace.

ACARS® ground stations are continually being replaced with integrated ground stations that support both ACARS® and VDLM2. In the United States alone, ARINC is operating over 300 VDL Mode 2 ground stations, and adding more each year to stay ahead of our customers’ needs. For ARINC, NextGen is already here and VDLM2 is ready to provide value to the Federal Aviation Administration (FAA) and to aircraft operators. ARINC’s VDLM2 network is built to enable the FAA’s next generation of air traffic control technology today, including revised clearances at the 65 FAA Tower Data Link Services (TDLSSM) airports.

In Europe, the European Commission (EC) has published a framework for the adoption of VDLM2 for CPDLC communications in the form of a Data Link Services Implementing Rule (DLS IR). The first milestone of this legislature has already taken effect as of 1 January 2011, which requires all new aircraft operating above Flight Level (FL) 285 to be delivered with a compliant system. The next critical date is 7 February 2013, by which time the ten core European Air Navigation Service Providers (ANSPs) will need to have implemented a compliant CPDLC ground infratsructure. ARINC is taking an active role in ensuring that the benefits of the new technology are maximised for the Air Transport Industry. In this context the role of ARINC will evolve from a traditional DataLink Service Provider to an industry partner with years of experience and a history of quality customer support.

ARINC has also deployed an operational VDLM2 network in Japan in cooperation with AVICOM AVICOM has been using ARINC’s VDLM2 system since 2003. The datalink cooperation between AVICOM and ARINC was solidified in 2009 with the signing of a comprehensive technology replacement agreement, awarded to ARINC in competitive bidding, As a result, ARINC has successfully enhanced Japan’s ACARS data link infrastructure with more efficient ACARS multi-service technology, which allows AVICOM to offer ATN/CPDLC services.

ARINC is making the migration to VDLM2 easy. New data link users or newly equipped aircraft can immediately use VDLM2. For existing aircraft, ARINC is providing ACARS® over AVLC (Aviation VHF Link Control)—or "AOA"—service, as well as ATN VDLM2 service. Because operators can continue to use ACARS® applications over the VDLM2 infrastructure when using the AOA service, they are only required to make avionics changes; the ACARS host systems and existing data link applications require no modification. Operators can transparently support their mixed avionics fleet and preserve much of their investment.

For more information, e-mail globalink@arinc.com.