Data Link: It Pays to Be an Early Adopter

Sept. 11, 2017

Business aircraft operators are reaping the benefits of using text messaging to communicate with ATC.

The FAA’s push to make communication between pilots and controllers more efficient took a major step forward last year when FAA rolled out text messaging for IFR departure clearances at 55 airports, and business aircraft pilots who are among the early adopters are reaping the benefits.

The system, known officially as Controller Pilot Data Link Communications-Departure Clearance (CPDLC-DCL), shifts certain routine exchanges between pilots and air traffic controllers – including departure clearances and weather-related re-routes – from voice to data. Pilots review ATC’s messages and can accept them via the push of a button, loading the information into the aircraft’s flight management system. Any changes can be communicated the same way up until the aircraft is ready to depart, giving controllers and aircraft operators a major time-saving tool during weather events or other situations that require rapid changes.

We are one of the only countries in the world now that can deliver re-routes to aircraft multiple times from the gate all the way up to departure.

Jesse Wijntjes, Data Comm Program Manager, FAA

“We are one of the only countries in the world now that can deliver re-routes to aircraft multiple times from the gate all the way up to departure,” says Jesse Wijntjes, FAA’s Data Comm program manager.

CPDLC-DCL (DCL) is part of a larger transition to Data Communications (Data Comm) to supplement voice capabilities throughout the National Airspace System (see sidebar). Voice communication frequencies used by pilots and controllers are becoming increasingly congested. This presents several challenges – including misunderstood communications and read back/hear back errors – that lead to pilot/controller communications inefficiencies. Data Comm will help change this.

DCL’s rollout was completed in December 2016, more than two years ahead of schedule and under budget, according to the FAA. Part of the reason: overwhelming support from both operators and controllers during the pilot phase to deploy the capability as quickly as possible. Feedback from users during the first few months of full deployment at the original 55 airports suggests that the system is delivering on its promise.

Saving Time

“There’s no question we’re seeing time savings during weather events that lock up airports,” says Chris Collings, senior program manager at Harris Corp., the Data Comm system integrator for the FAA.

Quantifying savings for business aircraft operators is challenging, in part because they don’t typically follow published schedules. But airlines do. Harris has compared block times of air carrier flights that use CPDLC-DCL with ones that don’t at the same airports and draws meaningful conclusions.

“Are [Data Comm users] doing better than the guys that got their clearances over voice? The data is telling us they are,” Collings says.

Empirical evidence from the front lines – controllers themselves – supports this. In September 2016, Washington Dulles International Airport (IAD) experienced a minor severe-weather avoidance plan (SWAP) event in which one northern fix was unavailable. (SWAP is a formal program developed for areas susceptible to disruption in air traffic flows caused by thunderstorms.) On that September day, 13 aircraft needed new clearances – nine with CPDLC-DCL and four without – noted Scott Starkey, president of the IAD National Air Traffic Controllers Association.

After the event, IAD controllers who reviewed the data found that the aircraft using DCL were delayed an average of 34 minutes, while the aircraft needing voice clearances waited an average of 52 minutes, Starkey said. While this single incident showed the value of Data Comm, Starkey believes the figures under-represent typical time savings, especially during SWAP events.

“The gap is normally much greater in a normal evening-shift SWAP situation,” explained Starkey. “Having multiple routes shut down inundates that flight data clearance-delivery person to re-issue verbal clearances. If two or three of the north fixes had gotten stopped, there might have been 15 aircraft that had to have verbal reroutes. All of the aircraft that were data-linked were done in a very short amount of time.”

During the Northeast’s SWAP season (typically mid-May through September), route closures are a regular occurrence, forcing controllers to find alternatives to keep traffic flowing. The quicker these alternative clearances can get relayed to waiting aircraft, the shorter the delays.

“If you operate in the Northeast, you’re guaranteed to see benefits from May to the middle of September every year,” Starkey says. “The routes between D.C. and New York are some of the most heavily traveled and regularly experience severe storms, and we provide extra staffing to help handle the delays. It’s the only way we can manage it.”

There’s no question we’re seeing time savings during weather events that lock up airports.

Chris Collings, Senior Program Manager, Harris Corp.

FAA data show that Data Comm saves an average of 13 minutes per flight in New York airspace during times of heavy traffic congestion, typically caused by bad weather. More than 7,500 flights receive the benefits of Data Comm each month at New York area airports – a number that continues to grow.

Unanticipated Benefits

While pilots welcome shorter block times, they point to some of the unexpected benefits DCL brings.

“Having DCL capabilities allows the flight crew, once logged on, to continue their pre-flight activities without having to monitor or contact clearance delivery on what have become very congested frequencies during those peak operating hours here in the Northeast,” says one captain with a Dulles-based business aircraft operator. “This is true, especially at airports like Dulles, Teterboro and Boston.”

The reduced pilot workload also brings a much-welcomed reduction in stress to the flight deck.

instrumentation with artsy overlay

“The ability to log on and request a clearance or receive a reroute has, in effect, reduced the quick-turn stress and increased pilot workloads associated with those multiple, failed attempts at obtaining clearances and or weather-related reroutes over congested voice frequencies,” the Dulles-based captain added. “The DCL capability has eliminated the cat-and-mouse game associated with trying to get a voice [pre-departure clearance] during those busy times, or when often there is no answer from either source.”

Like other parts of the NextGen program, DCL’s integration has required some procedural adjustments. Controllers learned quickly that, during delays, having Data Comm-capable aircraft in the same departure queue as aircraft relying on voice clearances was not the most efficient approach.

“If I have one long line of delayed flights awaiting clearances, but every other one is CPDLC, I don’t have any way to pull those out and get them to the runway,” Starkey says. Dulles, like several other airports, developed an airport-specific plan that keeps DCL users and voice-communications-reliant aircraft separated on the airfield. This ensures that data-link-equipped aircraft have direct access to the runway once they accept their clearances.

While using CPDLC-DCL is voluntary, benefits to all airspace users increase as more operators come online. The FAA says the program is on track to meet its goal of 1,900 domestic air-carrier aircraft equipped by 2019. In total, Harris says there are about 2,800 aircraft, including business jets and foreign-registered aircraft, using DCL regularly.

Data Comm is expected to save aircraft operators more than $10 billion over the 30-year life of the program. Also, DCL is projected to save the FAA about $1 billion in operating costs. In fact, the savings realized during the rollout freed up enough money to add seven more airports to the program: Buffalo, NY; Charleston, SC; Columbus, OH; Van Nuys, CA; Fort Myers, FL; Reno, NV; and Joint Base Andrews, MD, boosting the number of DCL-capable airports to 62.

Review NBAA’s CPDLC resources…

What is Data Comm?

Data Comm, also known as Controller Pilot Data Link Communications (CPDLC), is the catch-all phrase for digital communications (text-based messaging) between controllers and pilots. It provides a digital link between ground automation and flight deck avionics for safety-of-flight ATC clearances, instructions, traffic flow management, flight crew requests and other safety-critical messages.

Departure clearance (DCL) is the first major phase of the Data Comm rollout. Next will be sending automatic messages to enroute aircraft. Initial enroute services in high-altitude airspace are scheduled to start in 2019 and be available at all 20 enroute centers by 2021. This capability will enable controllers to provide pilots with frequency handoffs, altitude changes and reroutes.

“Data Comm, a NextGen Advisory Committee high-priority, high-readiness operational capability, is critical to reaching NextGen’s goal of time-based management,” according to the FAA.