With the FAA's new Data Communications (Data Comm) capability, controllers send digital messages to pilots in the cockpit. As with voice, these messages instruct pilots to fly a particular route, climb or descend to a particular altitude, contact a new air traffic control facility or follow other guidance. Digital messages will also carry flight crew requests and reports to controllers on the ground.

In addition, digital messages are well suited to handling complex instructions that can be processed by computers in the air and on the ground. They will also enable NextGen services such as improved rerouting capability, the management of intervals between aircraft and the automated handling of flight data that define the intended path of the aircraft.

With Data Comm, instructions are clear, quick and easily available for future reference. Pilots push a button to confirm the message and to communicate compliance. Pushing another button loads the new route into the aircraft's flight management computer.

Voice communication is labor intensive, time consuming and limits the ability of the National Airspace System (NAS) to meet future traffic demand. The use of Data Comm will lead to increases in NAS capacity and a reduction in flight delays. Data Comm will also enhance safety by reducing operational errors associated with voice communications, such as misunderstood clearances and instructions.

Data Comm Today

Prototype Data Comm equipment is being used to provide pre-departure clearances as part of ongoing trials at Memphis and Newark. Between 60 and 80 flights per day are using Data Comm at both airports, enabling the FAA to gather operational information that will improve the final system.

At Newark, a number of airlines are participating in the Data Comm tower trials, including UPS, FedEx, United Airlines and British Airways.

Initial Data Comm capabilities take advantage of available Future Air Navigation System (FANS) avionics. FANS has been used for years to enable controller-pilot communication in oceanic airspace. As a result, airlines can get benefits at no additional cost from equipment they have already installed.

Operators of equipped aircraft sharing the Newark departure queue with non-equipped aircraft can see the difference. The time saved by receiving digital clearances instead of voice instructions can make the difference between getting airborne before a thunderstorm closes the departure corridor and being stuck on the ground waiting for the storms to pass.

FedEx is the dominant air carrier at Memphis. A spate of arrivals at night is followed by a group of departures as soon as all of the packages can be sorted at the rate of several thousand per hour. It is critical that the final aircraft reach its unloading point as quickly as possible so the final sort can begin.

When sorting is finished, FedEx launches as many as 150 aircraft loaded with packages for destinations across the United States. When departure clearances can be sent to the cockpit via Data Comm, this process isn't slowed down by time-consuming voice radio conversations.

Data Comm Ahead

At the beginning of Fiscal Year 2014, the FAA agreed with the NextGen Advisory Committee (NAC) to continue operating the Data Comm prototype for 15 additional months at Memphis and Newark.

The FAA and the industry advisory group also agreed to deploy Data Comm to towers at 56 airports by the end of calendar year 2016. Deployment will begin in the summer of 2015 at Salt Lake City, Houston Intercontinental and Houston Hobby airports.

The FAA is working with the airline industry to encourage additional Data Comm equipage on flight decks. Initially, Data Comm will be used in conjunction with current air traffic control operations. This new digital messaging capability will also support air traffic management flow initiatives such as reroutes sent from ground automation systems to the flight deck. By automating these types of routine exchanges, Data Comm will simplify pilot and controller communications.

In addition to serving the communications needs of pilots and controllers, this Data Comm capability will keep airline operations centers and dispatchers informed of the latest clearances and routes being issued.

The FAA is moving ahead with the second phase of Data Comm, which will link aircraft in flight with the 20 air route traffic control centers in the continental United States. The FAA is committed to providing initial en route services starting in 2019. These services will expand to full operational capability at all 20 centers in 2021.

One of the most important capabilities en route Data Comm will enable is airborne reroutes. This should be particularly helpful when controllers are redirecting a group of aircraft around thunderstorms or away from airspace where there are other weather hazards such as turbulence or icing. Other messages handled via Data Comm will include new altitude and altimeter settings and instructions to fly special routes or to enter a holding pattern.

In addition, Data Comm will be used for transition communications as an aircraft leaves airspace controlled by one center and enters the airspace of another. About half of all radio calls between pilots and controllers now consist of pilots signing off with one controller and checking in with another. When digital messages take over this routine, radio chatter will be greatly reduced.

This will enhance safety as it will enable pilots and controllers to focus on other important duties. This will be particularly helpful in congested airspace where the radio chatter is so intense that pilots have to listen carefully for their own call signs to hear messages that apply to them.