The number of aircraft flying in Europe with controller-pilot datalink communications (CPDLC) equipment has about doubled in the past few months from 152 airplanes to more than 300, according to Eurocontrol officials. By contrast, CPDLC in the U.S. seems stuck in neutral, despite strong demand for the technology among airlines.

In the aftermath of 9/11 and a national recession, the FAA inevitably had to put on hold a host of advanced-technology initiatives as air carriers warned they might not be able to afford fleet-wide avionics upgrades until traffic levels returned to normal.

The FAA’s CPDLC initiative was among the most visible of the advanced-technology projects postponed last year in the wake of FAA budget cutbacks. Based on VDL (VHF datalink) Mode 2 technology, CPDLC seeks to replace standard voice communication with text messaging between controllers and pilots where possible. A trial of the technology in Miami had shown major early promise, but discussion of CPDLC in the U.S. has gone quiet since the project’s funding disappeared last summer.

Some in the industry are wondering whether the FAA needs to revisit CPDLC as passengers return to the skies in record numbers. This summer, American Airlines, Delta Air Lines and Southwest Airlines, the U.S.’s top three carriers, reported significant spikes in passenger volume as load factors and flights hit all-time highs.

Yes, fuel prices continue to hamstring the airline industry, but there is increasing evidence that major carriers are becoming more willing to invest in technology such as CPDLC, which they know will benefit them in the years ahead.

New Interest in VDL Mode 2

Arinc, the Annapolis, Md. company that was an early supporter of VHF datalink technology, reports that it has seen a recent uptick in interest for VDL Mode 2 technology. The company has been pumping money into R&D projects related to VDL Mode 2 infrastructure for the Americas, Europe and Asia, and, according to company officials, the world’s airlines have been deploying VDL Mode 2 equipment on their fleets in steadily increasing numbers.

“The demand for VDL Mode 2 has consistently exceeded our expectations, and it now represents the fastest-growing segment of our air-to-ground services,” said Dan Pendergast, director of Global- Link services for Arinc. Some 700 airplanes from about 20 airlines are now using VDL Mode 2 routinely, he said, including many of the major carriers based in Europe, North America and Asia. “This represents a 100-percent increase in just the past year,” he said, adding that VDL Mode 2 text messages will soon surpass two million sent and received a month.

Based on a 31.5-kilobyte-per-second data rate (compared with the 2.4-kbps rate of Acars), VDL Mode 2 holds the promise of delivering additional radio channel capacity to supplement Acars and ease voice channel congestion. These VDL Mode 2 channels are critically needed in much of the world’s crowded airspace, including the U.S., according to experts.

The technology Arinc and others are working on has sufficient capacity to handle the bulk of ATC text communications, as well as an array of data applications, such as automated diagnostic and maintenance reports and graphics-intensive weather services.

As of July, Arinc’s VDL Mode 2 technology was deployed at more than 200 ground stations on three continents. The datalink service is helping to relieve radio signal congestion in the upper airspace above six countries of Northern Europe, from coast to coast in North America and in Japan’s busy air traffic regions– where Arinc delivered and installed the ground stations for Avicom, Japan’s aviation communications provider.

Arinc has implemented CPDLC for Eurocontrol’s Maastricht Upper Air Center, including some of Europe’s most congested airspace. Officials in Europe appear eager to move forward with the technology, even if the FAA keeps CPDLC on the back burner. In a draft version of its latest report on the state of aviation in the U.S., called “Flight Plan 2006-2010: Making a Difference One Goal at a Time,” there is no mention of CPDLC.

The FAA’s CPDLC project budget cuts announced last year also caused postponements in the LAAS (local-area augmentation system) and Nexcom (next-generation communications) projects. At that time, industry officials close to the CPDLC program said they were deeply disappointed because the results achieved in the previous 19 months had been so positive in demonstrating the technology’s capabilities in alleviating flight-deck workload.

Now that the airlines appear to be ready for CPDLC, the question is whether the FAA will again be ready to spend the money needed to evaluate the technology.