Green taxiing: cutting carbon and costs

11 April 2012 (Last Updated April 11th, 2012 18:30)

A new green taxiing system, being developed by Safran and Honeywell, could help the aviation world cut carbon along with costs. Safran’s vice president of sales and marketing Frédéric Crancee gives Chris Lo the run-down of this high-profile project.

Green taxiing: cutting carbon and costs

As biofuels and other CO2-reducing innovations gather momentum, the idea that civil aviation can't do anything about its emissions is rapidly falling apart. As a result, regulatory bodies and other organisations are putting more pressure on the industry to mitigate its effects on the environment.

The extension of the European Union's Emissions Trading System (ETS) to the aviation industry at the beginning of 2012 has ruffled feathers among aircraft operators. US commercial airline representative Airlines for America (A4A) has been fighting the EU legislation in European courts without success, and in March withdrew another challenge from the UK's High Court in favour of trying to persuade US lawmakers to bring a new claim against the carbon reduction scheme under the framework of the International Civil Aviation Organization (ICAO), the industry's legal arbitrator.

Pressure is also mounting for airports, with voluntary carbon reduction initiatives like ACI Europe's airport carbon accreditation scheme putting the green performance of air hubs under greater scrutiny.

Instead of trying to swim against the tide of environmental awareness, forward thinking airports and airlines should be keeping an eye out for innovative technologies which could ease the transition to a lower-carbon industry. Of course, if these technologies can provide financial as well as environmental savings, so much the better.

Honeywell and Safran lead the push for green taxiing

"With fuel prices steadily rising, the environmental benefits of an electric taxiing system are directly linked with cost savings."

The combination of environmental and economic savings is exactly what aerospace giants Honeywell and Safran are aiming for with their joint project to develop a new eco-friendly taxiing system for airports worldwide. "Both Safran and Honeywell had been working on green taxiing for about three years, but separately," said Safran vice president of sales and marketing Frédéric Crancee.

"Both companies identified the interest within the market, and both looked for a technical solution and came to a very similar conclusion. So it made sense to setup a joint venture together."

Announced at the Paris Air Show in June 2011, the jointly-developed system would replace the current fuel-intensive pushback and taxiing process (short-haul taxiing operations consume five million tons of fuel a year, according to Honeywell) with an electrically powered system. The system is currently in the midst of an extensive testing and refinement process, with a commercial launch planned for 2016.

"The real purpose is to avoid both the tractor on the pushback and using the engine," explained Crancee. "We achieve this by using electrical motors fitted on the main gears - two motors per aircraft, one per main landing gear - and the power is driven from the APU [auxiliary power unit]. Since we do not run the engines, we have much lower emissions on the ground, and we also reduce the cost, of course."

Green taxiing: simpler, cheaper and eco-friendly

With fuel prices steadily rising, the environmental benefits of an electric taxiing system are directly linked with cost savings.

"The extension of the European Union's Emissions Trading System (ETS) to the aviation industry at the beginning of 2012 has ruffled feathers among aircraft operators."

Honeywell and Safran believe their system could facilitate savings of up to four percent on an airline's total block fuel consumption. So, as well as drastically cutting emissions during taxiing, there is a significant financial incentive for carriers looking to minimise their annual fuel bills. "Globally, the system could bring a saving of between $200,000 and $250,000 a year per aircraft," claimed Crancee.

Operationally, the system could prove extremely useful for airports due to its simplification of the pushback process, by which aircraft are pushed away from the airport gate to begin taxiing. This method is usually carried out by a large tractor which reverses the plane away from the airport, but with an electrical motor system on an aircraft's landing gears, this vehicle is not needed.

"Also, the pilot traditionally starts the engine during the pushback phase," Crancee added. "Of course, our system avoids any engine taxiing during that phase, so it means a reduction in fuel burn but also a reduction in the time it takes to carry out the pushback.

"Usually it takes roughly four minutes to perform a pushback, but since they do not have to start the engines that time can be reduced to two minutes. It's really important for the pilot and also for the airport, because the pushback area is a very busy and uncomfortable one, and if you can reduce the pushback time, it makes a difference for everybody."

Progress of the international Honeywell-Safran JV

If there were any concerns that two large conglomerates, each on opposite sides of the Atlantic (Honeywell is a US company, Safran is based in France), would be able to set aside their competitive instincts, they don't seem to have come to fruition. Crancee believes this is the best team for the task at hand.

"The combination of environmental and economic savings is exactly what aerospace giants Honeywell and Safran are aiming for with their joint project."

"The communication is good and both companies are of a very similar size and consider green taxiing in a very similar way," he said. "We both think about the full system at the aircraft-level, and what we want with Honeywell is to bring a global solution to aircraft manufacturers. Two large companies like us are able to provide that, to have the expertise, from the APU and the landing gears and the brakes, to the avionics and the controls.

"Our system is innovative but also it calls for a lot of expertise in different technologies. The Honeywell-Safran team covers all the required expertise, so we can bring a global solution to the aircraft manufacturer. Of course, it's up to the manufacturer to adapt it to the aircraft."

In November 2011, the joint venture (JV) announced it was beginning the first rolling tests of the system on an Airbus A320 in Montpellier, France. These tests were just the start, according to Crancee, who said they have paved the way for further refinement.

"Now we are using the results of the tests to tune the specifications and to refine the design of our equipment. We plan to carry out some demonstrations for TRL [test readiness level] six. That means it's a pretty mature design and nearly ready to be fitted to a flying aircraft. We intend to make this important step in the middle of next year."

There is a three-year gap between the JV's 2013 demonstration tests and the proposed commercial launch in 2016. This slow, steady development process is a conscious choice by the companies, who want to ensure the complex system is completely reliable when it's released. "It's not an easy project; we've had a lot of challenges," said Crancee. "For instance, these motors are installed in a sensitive area of the aircraft, on the landing gears where you have water, dust and heat from the brakes.

"We want to manage challenges like using a lot of simulations but also through a lot of testing. That's why the entry into service will be in 2016; between the demonstration next year and the entry into service we want to dedicate a certain amount of time to test the system on real-life equipment."

As the system continues to move towards its final completion, Crancee said the project has been getting a lot of interest and support from airlines and airport organisations, including Airports Council International's branches in Europe and Asia. With financial and environmental commitments snapping at the industry's heels, it's clear that Honeywell and Safran believe this system is offering the right benefits at the right time.

"When it comes to environmental performance, it will not be the same pace of change for all airlines, but I can tell you that when we discuss the system with airlines, some give priority to the green effect even over financial savings," Crancee explained.

"So it's clearly more and more important for airlines and airports, and if we can provide both economic savings and emission reductions, it's evident that the project will be interesting for them."