SeaTac Tower Ramps Up Ground Efficiencies

Rebecca Kanable
Published in: 

After five years, Seattle-Tacoma International Airport (SeaTac), operated by the Port of Seattle, has acclimated to having its own ramp tower to keep ground traffic flowing smoothly. With a total staff of ten, the tower operates 24/7 to control traffic into and out of 85 gates and 20 cargo hard stands.

"It's just part of the airport at this point," says Mark Coates, Port of Seattle senior manager, airport operations.

Coates likens the idea of operating without a ramp tower to using candles rather than electricity: It would be functional but not nearly as efficient.

The ramp tower, he notes, fosters multiple efficiencies: increased safety, fewer flight delays, lower aircraft fuel costs and reduced greenhouse gas emissions.

When Coates first considered a ramp tower about 15 years ago, the airport didn't have a suitable room available to house one, and costs for a new facility were too high.

Two major runway incursions in 2001, however, demonstrated the airport's ongoing need for a ramp tower, and a subsequent written notice from the National Transportation Safety Board punctuated the point.

Busy & Congested

Last year, SeaTac moved more than 31 million passengers and coordinated nearly 318,000 aircraft operations. Although it ranks as the 17th busiest U.S. airport, it has a smaller-than-average ramp area. In fact, it's been said that the 2,500-acre airport moves more airplanes per square acre of concrete than any other airport. These days, it's not unusual for ramp tower controllers to be monitoring and directing dozens of airplanes on the ramp at once.

"We have very close quarters," emphasizes ramp tower manager Earl "Paul" Hadler.

SeaTac's "non-movement" area was consequently prone to traffic jams. While many airports have runways that radiate in different directions from a centrally located terminal, SeaTac's 51-year-old main terminal has three parallel runways on one side. In addition, it has only one taxiway in front of the ramp, with a taxi lane running parallel. The space between concourses and the north and south satellite terminals accommodates only one plane. Ground traffic, for the most part, can only go in one direction. If one plane stops, it often blocks others.

New Air Traffic Tower

Just as the need for a ramp tower was officially established, the FAA announced plans to build a new, freestanding air traffic control tower at SeaTac. After the FAA vacated its tower located on top of the terminal, the Port of Seattle could use it for ramp tower operations. But before the new air traffic control tower could be built, a 6.8 magnitude earthquake caused about $6 million damage to the existing tower in 2001. For months, the FAA worked out of a trailer. But, Coates says, "With every negative, there's a positive."

As crews repaired the earthquake damage, they also brought the tower up to the latest building and earthquake codes, saving the Port of Seattle $6 million in the process, estimates Coates. The Port was consequently able to ready the former air traffic control tower for its new life as a ramp control tower with about $1 million of new equipment.

FAA Backup

When the Port of Seattle repurposed the facility, it patterned the ramp tower after an FAA tower, so air traffic controllers could move back in, if the need ever arose.

James Stark, FAA manager in SeaTac's air traffic control tower, confirms that the FAA is working with the Port of Seattle to develop an agreement that allows the FAA to provide air traffic control service from the ramp tower if the air traffic control tower becomes unusable or must be evacuated.

"Such an event is unlikely," Stark qualifies, "however, we want to be in the most advantageous position to provide the highest level of service possible if it does."

According to Stark, the Port of Seattle has equipped the ramp tower to provide exceptional ramp service, and that equipment could be used to assist the FAA in providing basic air traffic control services.

"We would not be able to provide the level of service that the equipment in the main tower allows," he notes, "but we would be able to control flights in and out of the airport."

With windows all around the control room, the nine-story ramp control tower provides a 360-degree view of the airport.

Choreographing the Dance

"The key to efficiency is the ability to know what's coming in and what gate an aircraft is going to go to," Coates says. "That's how we can put the dance together."

A variety of technologies provide the necessary information. Flight progress strips tell the routing of every aircraft leaving SeaTac. A commercial system called "PASSUR" from Megadata Corp. shows inbound air traffic 10 and 15 miles out, similar to the FAA's STARS. Inbound information is collected from the FAA's ASR-9 antenna. Sensis Corporation's ASDE-X (Airport Surface Detection Equipment - Model X) allows ramp tower controllers to see aircraft about three miles away before they touch down, then monitors them after they're on the ground.

A program unique to SeaTac permits ASDE-X readouts to include gate tagging so ramp controllers know each aircraft's intended gate. Knowing, for example, that Delta 235 needs to go to Gate S5, ramp controllers can help its pilot determine the best way to get to that gate. If an aircraft is parked at that gate, it can be moved before 235 pulls up.

"We have just about everything now that a ramp tower could possibly want," Hadler says.

Small Digital Voice Switch, from Denro Systems, controls all radio, telephone and computer voice systems in the ramp tower and is equivalent to the FAA's system. Information for all area airports including the local ASOS, weather sequence, ATIS identifier, RVR readings, runway in use, etc. is provided by IDS-5 from Systems Atlanta.

Collectively, the systems help ramp tower controllers answer pilot questions, which reduces call volume to the FAA tower. "Having all that information gives us the ability to work very smoothly and efficiently," Coates says.

On the ground, the FAA is responsible for managing aircraft operating on movement areas (taxiways and runways). The ramp tower takes responsibility for aircraft operating on the non-movement areas, which includes movement into and out of gates. A black and yellow non-movement area boundary line marks where the ramp tower's responsibility ends and the FAA's begins.

When the NTSB scrutinized the airport in 2001, investigators discovered that FAA air traffic ground controllers spent up to 50% of their time talking to airplanes in the non-movement area.

With SeaTac's ramp tower now taking these calls, Stark conservatively estimates the FAA eliminates more than 1 million radio conversations a year.

According to Coates, delays caused by pilots waiting to talk to a controller have consequently been eliminated. "Pilots talk, ramp tower controllers answer," he says.

With pilots and ramp tower controllers transmitting two or three times as an airplane arrives or departs, the Port of Seattle says airlines are saving operating costs for each aircraft.

Outside Expertise

Of the various business models available for operating a ramp tower, the Port of Seattle selected third-party management by Robinson Aviation Inc. (RVA). SeaTac's airlines fund the ramp tower service.

"The number one reason we brought in a third party was to bring in expertise," Coates explains.

With 500 air traffic controllers working at 93 FAA towers, RVA's main business is air traffic control. Adding ramp tower service, which it did starting with SeaTac, is a natural progression, comments RVA executive vice president Bill Peacock. RVA trains its air traffic and ramp controllers using the same language and control techniques that the FAA uses, Peacock explains, and many RVA controllers are former FAA or military air traffic controllers. The company is currently in the process of securing ISO 9001:2008 certification for its ramp towers. All of its air traffic control towers are already certified.

According to Peacock, more airports are starting to see the benefit of having a neutral third party responsible for deciding aircraft arrival and departure order to avoid favoritism or the perception of favoritism for certain carriers.

"We can provide the most efficient service to keep traffic moving and keep delays to a minimum," he says.

If, for example, weather delays a flight by 15 to 20 minutes, the ramp tower would tell the pilot to hold at the gate or proceed to a holding spot. That puts the airplane out of the way and makes way for other airplanes.

Input From User Groups

Efficiencies in SeaTac's non-movement areas are not only the work of ramp controllers, but also of user groups that include pilots, airport personnel and air traffic controllers.

Facts & Figures

Project: Ramp Tower

Seattle-Tacoma International Airport

Airport Operator:
Port of Seattle

Tower Operation: Robinson Aviation Inc.

Tower Size: 9 stories, with 360-degree windows on top

Cost: $1 million for new equipment

Benefits: Increased safety, fewer flight delays, lower aircraft fuel costs and reduced greenhouse gas emissions.

Special Circumstances: Port saved an estimated $6 million by converting a former air traffic control tower that was updated to new building codes after a 2001 earthquake.

At the groups' suggestion, the airport established primary one-way taxiways during peak traffic and adopted pushback procedures that better utilize its limited ramp space. In the past, airlines determined traffic flow based on what they thought was most convenient. Sometimes aircraft would push back and head in the opposite direction as an airplane trying to get into the gate.

Taxi lane lines were another topic of interest. The airport asked the groups if markings stood out enough and whether pilots know where they can hold and not be in the way of another airplane.

They also studied ground markings and drive lanes for vehicles. Subsequent changes help them move uniformly in one direction rather than any which way.

"We instituted unique markings to identify readily to the pilots the difference between the movement area and the non-movement area," describes Hadler, a former FAA air traffic controller.

Centerlines for all ramp taxi lanes are coded green; taxiway centerlines in the movement area are coded black. Other unique ramp markings are also green. "Those are all little things," Hadler says, "but they make a difference."

The Financial Side

Saving the airlines money was key to the ramp tower being deemed a success. And they are, in fact, doing so by moving into and out of gates more quickly.

The Port of Seattle estimates ramp efficiencies are saving its airlines 800,000 gallons of fuel and reducing greenhouse gas emissions by 850,000 tons each year.

Airlines can even witness ramp traffic first-hand. If an airline is having an issue, personnel can study operations from the ramp tower to help understand why a procedure isn't as efficient as it could be.

Procedural changes made after spending a day in the tower have helped a number of airlines shave one to two minutes off ramp times, Coates reports. And saving time means saving money.


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Giving back to the community is central to what Charlotte Douglas International Airport and its operator, the City of Charlotte Aviation Department, is about, and last year was no different. 

Throughout 2022, while recovering from the COVID-19 pandemic, we continued our efforts to have a positive impact on the Charlotte community. Of particular note, we spent the year sharing stories of how Connections Don't Just Happen at the Terminal - from creating homeownership and employment opportunities to supporting economic growth through small-business development and offering outreach programs to help residents understand the Airport better.

This whitepaper highlights the construction projects, initiatives, programs and events that validate Charlotte Douglas as a premier airport.

Download the whitepaper: 2022 Charlotte Douglas International Airport Report of Achievement.



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