Aviation contributes around 2% of global greenhouse gas emissions, a percentage that the Air Transport Action Group predicts will increase without switching to a sustainable fuel (SAF). However, for a business, sustainable fuels are not the only way to combat the use and emissions of aviation fuel.
At Aircraft Towing Systems World Wide (ATS), a new system approaches the problem from a different perspective. The Oklahoma-based company developed a concept that uses electric winches that travel along underground tracks on airport runways and taxiways to pull planes to and from the terminal. ATS has been testing a prototype at Ardmore Industrial Airpark in Oklahoma since mid-year.
According to Vince Howie, ATS innovation offers the potential for environmental savings and compliance with future emission limits. The project is also on schedule. The European Union Aviation Safety Agency (EASA) has already published targets for unpowered taxiing by 2050. Ultimately, the Federal Aviation Administration (FAA) will also do so.
Boeing 737s and Airbus A320s make up about 80% of the commercial aviation fleet and consume about 9 gallons of fuel per minute while taxiing, with an average taxi time of 16 to 27 minutes. In summary, when operating at its normal capacity, an average large commercial airport could see this flow 800,000 to 900,000 times per year.
“If an airplane uses 9 gallons of fuel per minute for 16 minutes, 800,000 times a year, and the fuel costs $ 2-3 per gallon, you’re talking real money,” Howie explains. “The savings our system will provide are enormous,” he adds, noting that the system not only saves fuel but also reduces emissions. Pilots can turn off the engines while the electric trailers pull the plane.
“Emissions are reduced by up to 80% by shutting down the main engines,” he says. “The APU is the only thing that keeps running to power the air conditioning, the crew and the passengers.”
Stopping the engines also reduces noise. “The noise reduction is immediate and the reduction is huge when you shut down the engines,” Howie adds. “Our system also reduces collisions because we follow when we bring the planes into the terminal.”
The ATS system also reduces engine service intervals, as pilots shut down aircraft engines on the ground. “This allows for additional savings,” he says.
Build a prototype
When the COVID-19 pandemic broke out, ATS began work on its prototype. However, the situation delayed the project for almost a year, but ATS finally began on January 14, 2021 and began construction of the test area at Ardmore Industrial Airpark.
The modular design of the system allowed construction crews to install prefabricated sections. The installed sections become immediately operational.
When complete, ATS will use an electric subway cart and a surface towing platform to cross the U-shaped channel to move planes to and from the airport runways and gates without depending on aircraft engines. A 400 horsepower Borg-Warner electric motor, used in electric cars, powers the cart and tow cart.
ATS purchased a 727 to demonstrate its innovation in towing.
How the ATS system works
Howie describes the ATS system as a modern rail system for aircraft. The tow truck is on a monorail at the bottom of the canal, which is underground. Two sets of hydraulic motors, one at the front and one at the rear, move the cart.
When an aircraft lands, pilots roll onto the taxiway and drive the front wheel of the aircraft onto the ATS trailer, resembling a round disc with ramps at each end. This secures the aircraft in place.
“When that happens, the main engines are shut down and the trailer does the job,” Howie explains. “A round tow truck never puts pressure on the front landing gear. There is a positive control of the plane. The system can pull or push the plane in different directions, but the pilot remains in control ”. A foot of snow or an inch of ice operates the system.
By designing a roll and rollback system, explains Howie, ATS has broadened the scope of the product.
“We were targeting 34 airports in the United States for the entire system; hubs like Dallas or O’Hare and places like that, ”he says. “But we had 22 smaller airports that said they needed an electric pushback system, so we developed a curved rail that allows us to bring a plane in and turn it around when we push it back. About 200 American airports could benefit from the pushback system ”.
The system uses vehicles capable of handling regional-sized aircraft up to an A380. Whether the ATS system is part of the decarbonization trend will depend on the future and on the orders placed.