Communications, Navigation & Surveillance (CNS)
The Sound of Silence: NextGen Communications
NBAA Flight Plan intervew about NextGen with John Kefaliotis at ITT Exelis
January 23, 2012
If you’ve ever been in the cockpit as your aircraft transitioned through a very busy patch of sky, you’ve no doubt noticed the rapid-fire communications between controllers and flight crews as they issue and acknowledge complex instructions on speed, heading and altitude. It’s a carefully choreographed dance in three dimensions and in some places, the number of aircraft operations mean controllers are working near capacity. But starting in 2015, the cacophony of controller instructions and pilot read-backs will begin to fade as a vital aspect of the FAA’s NextGen concept becomes a reality: data-based communications.
“With the voice channel, there’s always the potential for error,” explained John Kefaliotis, Vice President of Next Generation Transportation Systems at ITT Exelis. “Routine voice communication and clearance delivery is also a significant part of the controller’s workload.”
More importantly, Kefaliotis said, voice communications – especially in busy airspace – is not suitable for the complex clearances that will be required under NextGen. Issuing instructions that include specific latitude-longitude fixes would be simply too time-consuming and far too prone to error.
So over the next six years, FAA will construct a ground-based digital communication network that will enable both voice and data streams between the ground and the cockpit.
“The idea is to issue hand-offs, routine instructions and complex fixes over the data stream instead of the voice channel so that there’s a reduction in routine level communications. That allows for more cognitive time both on the ground and in the air,” Kefaliotis stated.
Much of that data will actually be transferred directly from the ground into the aircraft’s flight management system, he said. “The ability to transfer clearance information is enabled by the data channel, which is integrated into the flight management system, allowing the pilot to preview a clearance, then hit a button and load it into the FMS.”
Data-based communication between controllers and pilots is already in use for overseas travel, where aircraft are not under radar surveillance. The Future Air Navigation System (FANS) was developed by the International Civil Aviation Organization (ICAO) and first implemented in 1996 to facilitate better communications and tighter spacing between flights along Atlantic, Pacific and polar routes.
Domestically, three companies are competing for the FAA contract to build the ground-based network necessary for digital aviation communications: ITT-Exelis, Lockheed-Martin and Harris Corp. The FAA is expected to award the integration contract in June.
Another benefit of data-enabled communications will directly affect the bottom line of flight operations nationwide, Kefaliotis said.
“Trajectory-based operations” allow operators to maximize both economy and time during flight. Clearances will be tailored to more exactly match an aircraft’s optimal rate of climb, cruise altitude (and variations in cruise altitude given the aircraft’s weight changes related to fuel burn) and best rate of descent.
“The notion of trajectory-based operations in the national airspace takes into consideration the optimal trajectory of an aircraft. Today, there’s a lot that keeps that from happening,” Kefaliotis said.
