With airlines continually looking for ways to curb their use of fuel for economic and environmental reasons, a U.S. company is offering an unorthodox solution for taxiing. Oklahoma-based Aircraft Towing Systems World-Wide (ATS) is developing a permanently installed infrastructure system that would allow aircraft to shut off their engines at the taxiway for automated towing to the gate.
The system, which has undergone development for the past six years in cooperation with Oklahoma State University’s New Product Development Center, involves an electrically-powered pull cart that runs on an underground monorail attached to an above-ground tow dolly. According to company CEO Vincent Howie, the system would simply drive an aircraft's nose gear onto the dolly, which would then raise via hydraulic pumps and automatically chock the nose wheels in place. The pull cart, powered by electrical circuits embedded in the walls of the underground channel would then provide the motive force to move the airplane.
ATS uses a test track at Oklahoma’s Ardmore Industrial Airpark consisting of a 358-foot-long powered channel with two straight lengths flanking a 90-degree bend to test the system’s gate pushback capabilities. The company acquired a decommissioned Boeing 727 to use as a tow test subject.
Last month, ATS powered up the pull cart’s motor for the first time at its Tulsa, Oklahoma, facility and will test its linkage and connectivity with the tow dolly. It expects to deliver the combined unit to Ardmore and start testing in the channel by August, with towing of the 727 slated to follow by the end of the summer. Exhibiting at Farnborough with the Oklahoma Chamber of Commerce (Stand No. 2322, 2523) ATS anticipates a six-month test schedule and plans a public unveiling to take place in the first quarter of 2023.
Howie characterized the system as capital-intensive, with the channel installation costing $1,000 per linear foot. The company has developed a simulator model that will show the optimal placement of the channels based on traffic flow and gate movements and will calculate channel lengths. In addition, each pull cart/tow dolly tandem would cost about $250,000. “We would sit down with each individual airport and calculate what’s the maximum number of aircraft that would be on the ground at any one time, and then that would probably be the high side for what we would do for the number of pull carts and tow dollies,” Howie told AIN. Since the channel sits below ground, aircraft can continue to operate normally at the airport without using the system if necessary.
Howie explained that the system would allow operators to quickly recoup their costs based on fuel savings alone. “If you think about it, 80 percent of the commercial fleets out there are made up of [Boeing] 737s and [Airbus] A320s, and those aircraft burn about 9 gallons of fuel per minute during taxi, and the average taxi time in the United States is somewhere between 16 and 27 minutes depending on the airport,” he said. Major airports can host hundreds of thousands of movements per year, so eliminating fuel burn during taxiing would result in hundreds of millions of dollars in saved fuel costs and untold CO2 emissions. The manufacturer also notes the system’s control of all aircraft movements during taxi and gate operations can reduce the chance of human error and increase the pace of activity.
Along with gate arrivals and pushback, operators can use the ATS system for specific point-to-point transfers, such as taking aircraft through deicing loops. Howie described another example of an airline that has a maintenance facility in Tulsa, located more than a mile from the terminal. There, taking in an aircraft for overnight maintenance could involve as many as 16 people. Installing the ATS system as a spur track to the maintenance facility could reduce the manpower required to as few as one person.
The company remains in discussions with several airports in the U.S., including Will Rogers World Airport in Oklahoma City, and Baltimore/Washington International Thurgood Marshall Airport. As it ponders its future expansion, Denver International Airport faces resistance from its airline tenants over plans to locate Runways 6 and 7 three miles from the terminal due to the associated taxiing costs. Through an airport consultant, ATS is pitching the system as means to ameliorate the situation, having them towed to the runways instead of taxiing under their own power.
In Spain, the company is also working on a proposal to install a pushback system at one of the gates at Madrid–Barajas International Airport.
Depending on the airport and the size of the aircraft it can accommodate, ATS will offer the system in three sizes: large for anything from an Airbus A380 to a regional jet; medium for aircraft up to the ubiquitous 737s and A320s; and small for regional and business jets. “Not every airport has the ability to handle 747s, and with the smaller size you can have a smaller channel,” said Howie. ‘The channel really drives a lot of the cost.”
