DAVID LEARMOUNT / LONDON
Long-standing US plans for an air-ground datalink to take the pressure off air traffic control voice communications look certain to be delayed.
The US Federal Aviation Administration is unable to confirm dates for advancing controller-pilot datalink communications (CPDLC) beyond a successful Miami-based preliminary trial.
This uncertainty has led to Eurocontrol concern that the mutual aim of global interoperability may not be met. "The USA has yielded ATM [air traffic management] leadership to Europe," American Airlines CPDLC manager Capt Brent Blackwell told the ATN 2003 conference in London, UK, in September, adding that deferrals of US communications programmes are "straining the basis for investment" by manufacturers in developing the necessary equipment.
The FAA's official strategy for providing more voice channel space as well as CPDLC remains VHF datalink mode 3 (VDL-3), a digital radio communications system that can carry voice and CPDLC on the same signal. VDL-3 was not used for the Miami CPDLC trial, which was more a test of whether pilots and controllers liked messaging in text form - which they reported they did. The airlines used their ACARS (airline communications addressing and reporting system) datalink, normally used for management/operations messages, technical data and oceanic position reporting.
The new equipment programme, known as Nexcom, is not popular with the airlines because of its cost, which, in turn, has made suppliers less keen to invest in the development remaining to be completed, but the FAA insists: "We are not stopping work on Nexcom."
The International Air Transport Association says it wants to start with VDL-2, and for development work on VDL-3 and the automatic-dependent surveillance-broadcast based VDL-4 to be extended to produce a more advanced successor for VDL-2. Meanwhile, US low-cost carrier Southwest Airlines has started a VDL-2 fleet-equipping plan instead of using the capacity-strapped ACARS analogue VHF datalink.
Source: Flight International
