Can 'Taxibot' Deliver Airport Fuel, CO2 Reductions?

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taxibotbigCan IAI's new robot help airlines save money and cut carbon emissions by changing runway procedures? EADS Airbus intends to find out.

Airliners all over the world use their main engines to taxi into position at runways and gates. EADS Airbus claims that fuel consumption from this practice is forecast to cost around $7 billion by 2012, while emitting approximately 18 million metric tonnes of CO2 per year. The effect of those engines also acts like a super-size blower, creating an incidental problem of Foreign Object Debris damage to nearby planes and equipment that's estimated at $350 million per year.

The cost of fuel, and concern over the industry's carbon emissions, are already creating changes in the industry. Back in December 2006, "Branson: Airlines Can Cut CO2 Emissions 25% in 2 Years" covered one corporate shift:

Branson said the airline industry can reduce its CO2 emissions by about 25 percent over the next two years. Branson said he has started towards that goal by towing planes to the runway with an electric tug instead of taxiing planes.

Other ventures are in the works. Chorus Motors subsidiary Wheeltug offers a system that modifies airliners to allow APU-only (Auxiliary Power Unit) taxiing, and is partnered with Delta Airlines. Another, more recent entrant involves Israel Aerospace Industries and EADS Airbus.

IAI's Taxibot is a a tow-bar-less robotic tractor that would allow both wide and narrow body commercial airplanes to taxi to and from the gate and the runway without using their jet engines, while remaining under full pilot control at all times and removing all hazards to ground vehicle drivers. Unlike systems like Wheeltug, the system requires no modifications to airliner fleets. It does share the advantage of letting the pilot move and steer the aircraft on the ground, using the same controls and motions they've been trained to use during full engine maneuvers.

The Taxibot demonstrator is currently powered by 2 diesel engines, which drives 6 hydraulic motors in a typical "one in each wheel" hydrostatic drive architecture. For the prototype and serial production, IAI says that other hybrid electric solutions will be considered.

EADS and IAI report that an initial evaluation of this concept has shown promising results. IAI believes "Taxibot" could reduce annual fuel costs from $8 billion to less than $2 billion, CO2 emissions from 18 million tons to less than 2 million tons per year, and noise emissions by a significant margin. That last component is a less attention getting environmental component, but its significance will rise. The US Department of Transportation-led study "Trends in Global Aviation Noise and Emissions from Commercial Aviation for 2000 to 2025" predicted that despite noise level improvements in next-generation airplanes, the number of people forced to deal with serious aircraft noise will rise from 24 million in 2000 to 30.3 million by 2025.

A June 2009 Memorandum of Understanding between IAI and EADS aims to take the next steps, and validate Taxibot's potential. Airbus will participate in the feasibility studies, using an Airbus-owned A340-600 long haul airliner as the test subject. In addition to the ground tests in Toulouse, France, the MoU assessment phase will also cover regulatory, legal/product liability, environmental, and financial evaluations.

If all goes well during those 2009 assessments and subsequent operational demonstrations, IAI and EADS would look to a 3-way partnership with a vehicle manufacturer, in order to certify, produce, and sell Taxibot tractors to airports. Under current plans, Taxibot would be ready for first deliveries by the Q3 2011.

A ground tractor that can pull an A380 would also be able to handle almost all military aircraft, but several issues stand in the way.

One is the fact that physical time on the flightline matters more to military customers, since the accompanying safety and logistics issues involved can be so serious. Another is market size. Despite IAI's strong military background, the firm says that there are no plans to market the Taxibot solution for military applications, "since the biggest savings in fuel and CO2 are in the commercial mainliners market."

That would change if a major military customer expressed interest, of course. Something that's entirely possible, given the rising concerns around long-term fuel costs, and their effect on air forces in particular.

Environment + Energy Leader