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Airbus signs MoU with EGTS for electric taxiing solution for A320 family; projected fuel saving up to 4% per trip

Using the aircraft’s Auxiliary Power Unit (APU) to power electric motors on its main landing gear, the “eTaxi” solution is projected to save fuel and reduce CO2 emissions during an A320 Family jetliner’s ground operations by up to 4% per trip. Click to enlarge.

As part of on-going research and development into future technology options, Airbus has signed a memorandum of understanding (MoU) with EGTS International (Electric Green Taxiing System), a joint venture company between Safran and Honeywell Aerospace formed in 2011, further to develop and to evaluate an autonomous electric pushback and taxiing solution for the A320 Family. (Earlier post.)

The agreement marks the selection of EGTS International’s Electric Green Taxiing System to be evaluated as a new option on the A320 Family—referred to by Airbus as eTaxi. This option would allow the aircraft to push-back from the gate without a tug, taxi-out to the runway, and return to the gate after landing without operating the main engines.

eTaxi will use the aircraft’s Auxiliary Power Unit (APU) for power. One wheel on each main gear is equipped with an electric motor, reduction gearbox and clutch assembly to drive the aircraft, while unique power electronics and system controllers give pilots total control of the aircraft’s speed and direction during taxi operations.

The system comprises the modified APU (to generate the additional power required for the system; Wheel Actuator Control Unit (WACU); Wheel Actuators; Pilot Interface Unit; and EGTS controller.

Key performance attributes include:

  • ≈20 knots speed in 90 seconds (≈18 knots @ MTOW, maximum takeoff weight)

  • 10 knots speed in 20 seconds for active runway crossing

  • Breakaway torque @ 1.5% slope at MTOW

  • No reduction in reliability or dispatch performance

The eTaxi option will offer several operational and environmental benefits for the A320 Family:

  • Per trip, the projected fuel savings and CO2 reductions would be approximately four percent;

  • It would contribute to significantly more efficient taxiing operations and save around two minutes of time on pushback; and

  • Taxiing-related carbon and nitrous oxide emissions would be cut by more than half.

Over the next few months the partners will jointly develop and present a global commercial case and implementation plan to determine the feasibility of an electric taxiing solution for the A320 Family. To this end, Airbus and EGTS International are reinforcing their existing teams to finalize validation studies, define specifications and converge on market requirements for a fully tailored forward-fit and retrofit technological solution.

Following our demonstration of the technology at this year’s Paris Airshow, this MoU marks the next critical milestone in the advancement of the Electric Green Taxiing System as an option for Airbus’ A320 Family, by securing Airbus’ support in the development of the system. Airbus will provide extremely valuable insight to facilitate a seamless integration into the aircraft.

—Brian Wenig, EGTS Programme Vice President, Honeywell Aerospace

Airbus invests approximately €300 million (US$413) annually in keeping the A320 aircraft competitive and efficient. More than 10,000 A320 Family aircraft have been ordered and more than 5,800 delivered to operators worldwide.



An excellent idea to reduce fuel consumption, air and noise pollution at airports.

Others will follow?

Hope that Boeing select and install improved batteries.


But where will the electricity for this come from? Aircraft do dispose of residue fuel so to not foul the engines. I've heard it proposed that this should be burned in runway tugs that are outfitted with Sterling engines. Fuel cells have come a way since then. I didn't know landing gears were fitted with differential gears, or that + electric motors wouldn't add unacceptable weight. Must be that airlines are spending a HUGE amount of time waiting on runways with engines on, at obsolescent and overcrowded airports. maybe they sould bring back seaplanes, which were popular before airports were even built.


This has been proposed for some time, but this sounds like the big one.

I wonder

will it be retrofittable to existing A320's?

What journey lengths the 4%fuel savings refer to?

Does it have regenerative braking ?

I suppose it is very early days for this stuff, and it will take them 10-20 years to get it fully developed.

I have a notion of an electronic catapult like the emals system for the new US aircraft carriers, only 2km long, which can be used to boost an aircraft on takeoff.

This would be very useful in hot places like the gulf airports in Summer when it can get to 45-50 degrees C, degrading engine performance.

The catapult does not have to provide 100% of the takeoff power - even 20% would be a help, they already have powerful engines and a long runway.

I suppose the problem with that is the fire, retract, fire, cycle could disrupt airport operations.

But it is tempting as it would enable planes to take off with more fuel on board, without more powerful engines.

[ You would probably need a much stronger nosewheel assembly ]


Funny how the "green" taxiing system is being advertised on a fully painted plane --- with the weight of paint on the plane resulting in massive amounts of wasted fuel over the life of the aircraft --- and with electric motors built into the wheels whose additional weight also results in massive amounts of fuel burned over the life of the plane while in flight. Where's the logic? Anyone? Bueller?

But where will the electricity for this come from?

It comes from the aircraft's APU (Auxiliary Power Unit).  The APU is far more efficient than the main engines at low power levels, and the tires are reacting against the unyielding pavement instead of slippery air.  Generating a pound of static thrust with a motor attached to a wheel is far more efficient than using a turbofan.

I suppose it is very early days for this stuff

Not so much.  I would expect lots of retrofits very quickly.

Funny how the "green" taxiing system is being advertised on a fully painted plane

Paint does reduce corrosion of the underlying metal, so there is a reasonable justification for it.


EP wrote: "Paint does reduce corrosion of the underlying metal, so there is a reasonable justification for it."

Is there any evidence whatsoever that planes operated by American Airlines with the previous paint scheme (paintless) were plagued with erosion?

"When it comes to weight, each pound shed from a plane saves the company [American Airlines] 14,000 gallons of fuel a year."



Did you read the article that you linked to?

American wasn't running bare aluminum (which would have quickly oxidized). The reference to paint weight in the article is in comparison to stickers. Nobody is running unprotected aluminum for very good safety and economic reasons.

The other quote you provide is misleading. They are talking about saving a pound on each of 700 planes. That means that shedding one pound saves 20 gallons of fuel per year, or 208ml per day, or 70ml per flight. It's still a large amount, but it's 700 times less than the quote implies.

The logic of using the APU for taxiing is that it will save roughly 4% of the fuel used in a short/medium haul (A320) flight. The electric motors do weigh something, but it's probably less than the amount of fuel burned by jet engines during normal taxiing after landing.


Actually, re my comment about where the electricity is going to come from, I'll do you one better. An APU and fuel (kerosene purged from near empty tanks) are mounted in a Roomba type robot vehicle with an attachable electric line. This propels the landing gear and the passenger compartment, even if the main engines are completely turned off, or just warming up. The aircraft APU takes over at the last minute.


The on board APU is apparently 5 times more efficient than using the large turbo fans engines to push back and taxi an Airbus 320 or equivalent aircraft.

Assuming that an average of 20 minutes of large engines usage time, per arrival and departure, could be saved from push back/docking and taxi time, 200 Kg to 400Kg of fuel could be saved per flight.

That should be about enough to offset the extra weight of the modified APU and electric drive. The savings would be from less fuel consumed and less emissions created per flight and less ground support required.


We've been talking about doing this for as long as I've been in the Aviation Industry. Yet, nobody has seen fit to produce a viable production setup.

One thing to be mindful of, the main engines often need 5 or more minutes of warm up prior to takeoff. At my home base (Palm Beach International Airport) , the taxi is often less than 5 minutes. So, cold engines are started during pushback. While a 4% fuel savings may be possible during some congested and short routes, others won't see any savings at all and will pay the penalty of additional weight and maintenance.

In years past, there was quite a bit of talk about a hydraulic system driving the nose wheels. I think the conclusion back then is that it was not worth it. I wonder what's changed? Possibly the long delays today...


The 'average' taxi time (over the 4 to 5 minutes warm up) is 20 minutes and rising, where A-320 and equivalent jets are operating.


That, and shutting down the main engines immediately after landing would save the fuel used taxiing to the gate (and perhaps holding for traffic on runways being crossed).


Airports equipped with ILS-IIIC or better is enough to guide landing plane(s) to the assigned gate(3) much like an e-vehicle with autonomous drive. Of course, the pilots would still monitor the operation and intervene on an as required basis.

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