John Croft Washington

A 2015 mandate for controller-pilot data link communications (CPDLC) in European airspace above 28,500 ft.—Flight Level 285—will represent the most lucrative opportunity in the airline retrofit market in 2013 for avionics makers.

Called Link 2000+, the rule calls for the installation of airborne data link systems that can process nearly 100 uplink and downlink messages, most of which are pre-defined text messages for “non-critical” communications. Over a VHF voice link, those non-critical contacts can occupy 50% of a controller's time, impacting capacity. Having “canned” text messages will also help to reduce miscommunications and stuck-microphone issues.

Typical CPDLC uplink commands include “climb to,” “descend to” and “fly heading” requests, which pilots respond to by clicking “wilco,” “unable” or “stand-by” buttons. Canned requests for pilots to send to controllers include climbs or descents and weather deviations. Both pilots and controllers can also send free text messages for events not covered by pre-defined messages. If a microphone is stuck in the “transmit” mode, blocking voice communications, controllers can send pilots a text message to investigate the situation.

According to Honeywell Aerospace, the controller workload reduction will result in an upper airspace capacity increase of 11% when 75% of the participating aircraft are equipped. “The second benefit, on the pilot's side, is that there is reduced workload and fatigue from radio telephony,” says Aileen McDowall, director of air transport and regional technology sales at Honeywell. “Currently, pilots have to listen to each radio message and only one in 20 messages is applicable to their aircraft.”

While new aircraft were required to have the required equipment installed from the factory as of Jan. 1, 2011, the existing fleet was given until Feb. 5, 2015, to equip. Air navigation service providers in the region are required to have the ground infrastructure in place by early 2013 or 2015, depending on their location (see map, page 130), though there are some indications that the February 2013 date is overly optimistic.

For many airlines, 2013 is a “do-or-die” year for scheduling fleet upgrades for the 2015 mandate, in order to overlap the Link 2000+ maintenance work with regularly scheduled C and D heavy maintenance checks rather than to risk taking aircraft out of service unnecessarily.

In the cockpit, the Link 2000+ retrofit generally requires changes or additions in four areas. The aircraft must have a third radio that is VHF Digital Link Mode 2 (VDLM2)-capable; it must have a multi-function display that can show the text messages and allow for pilot responses; it must have an aural or visual alert that lets the pilots know a message has arrived, and it has to have a communications management unit (CMU) that acts as the CPDLC router and application. McDowall notes that the CMU “is the brains” of the operation.