Five U.S. airlines have signed on to participate in the Federal Aviation Administration’s Data Comm equipment initiative, bringing the effort to 80 percent of its targeted number of airframes, according to contractor Harris. The company revealed the first airline to commit–United–at the Air Traffic Control Association conference last month. Non-disclosure agreements prevented it from immediately identifying the others.

Harris is administering the equipment initiative as part of the Data Comm Integrated Services (DCIS) contract the FAA awarded the company in September last year to build a nationwide data communications network for ATC messaging. The program originally specified that $80 million would be made available in seed funding to equip early-adopting airlines. Participating carriers have agreed to equip their aircraft over six years with Future Air Navigation System (Fans) datalink communications, now used mainly in oceanic airspace, using VHF digital link mode 2 (VDL Mode 2) as the communications medium. The system relies on the ground station networks Arinc and SITA use to provide airline communications.

“The incentive is in the form of a rebate, when [airlines demonstrate] that they’ve appropriately equipped their aircraft for the Data Comm program,” explained John O’Sullivan, Harris vice president of NextGen initiatives. “That includes two major components: the Fans component and the VDL Mode 2 digital radio component. So we’re [offering incentives to adopt] Fans over VDL Mode 2.”

Harris executives said the FAA’s target is to outfit approximately 2,000 aircraft for ATC data communications under the equipment initiative; 80 percent of that target would be about 1,600 aircraft. United plans to equip up to 397 aircraft, more than half of its mainline fleet. Separate from the DCIS program, United is among airlines participating in the FAA’s data comm departure clearance (DCL) trial at Newark Liberty International Airport, one of two airports, with Memphis International, at which the FAA has installed the needed ground infrastructure for the demonstration.

The FAA plans to deploy data communications at 57 ATC towers to send departure clearances to pilots starting in 2016, and at air route traffic control centers for en route communications starting in 2019. The next milestone for the DCIS program will be the start of integration testing with the associated tower datalink services (TDLS) and en route automation modernization (Eram) automation platforms early next year. Harris will conduct laboratory testing at the FAA Technical Center near Atlantic City, N.J., at its headquarters in Melbourne, Fla., and at other sites.

“This is essentially a message string service, so it relies on portions of application programs like Eram and TDLS,” O’Sullivan said. “You’re testing the message string over the applications program through the networking elements and the security gateway elements and up to the aircraft.”

With the completion of testing and integration, the FAA will roll out the tower-based data comm service to three “key” sites: Salt Lake City International Airport and Houston’s Hobby and Bush Intercontinental airports in the third quarter of 2015. The remaining tower sites will follow.

“I think the program is proceeding quite well,” O’Sullivan said. “I’m just thrilled [about] how excited the airlines seem to be about it, relative to their commitment. For these airlines to equip for Data Comm is a discretionary investment on their part and the success so far has been encouraging.”