Why use giant airplane engines when a small diesel will do?Airplanes waste a lot of fuel on the ground. To taxi around airports, from passenger gates to runways, planes are powered by their main engines which simply aren't optimized for that task. This creates a lot of unnecessary CO2 emissions, air pollution, and noise. We've already written about how this could be improved by having planes taxi with only one engine turned on, but there's an even better way to solve this problem: Israel Aerospace Industries has created the TaxiBot, a partly automated tug vehicle that could allow planes to move around on the ground in a fuel-efficient way, and while leaving the plane's pilot in control.
Makes so much sense, I wonder why it isn't already widespread
Here's how it works: "Taxibot, operated by a driver, lifts the aircraft's nose wheels for pushback but for taxiing pilots control the tug to avoid unnecessary use of engines. Pilots steer the tractor via the nose-gear tiller in the cockpit, with aircraft wheels resting on a rotating platform, translating nose-gear deflections into directional changes for the tug. Aircraft wheel brakes are used for deceleration. Forward speed is also controlled by braking." (source)
This video gives an overview of TaxiBot's capabilities;
The benefits could be huge:
With the high price of aviation fuel—a tonne can cost more than $1,000—the savings at a busy airport could be large. At some airports the passenger gates can be several miles from the runway. All told, the world’s airlines spend $7 billion-8 billion a year taxiing between passenger gates and the runway, says Yehoshua Eldar, who is in charge of business development at IAI. The TaxiBot, though, uses just 20-30 litres of fuel for a typical trip.(source)
On top of reducing CO2 and smog-forming emissions and noise pollution, it would also extend the life of engines by reducing the risk of them being damaged by 'foreign objects'.
The TaxiBot concept would be even better if the tug vehicle was electric. Maybe this could be done by swapping battery packs so that it can operate all day without having to stop to recharge.
Another cool technology that could be combined with this to make air travel greener is: Computerized Air-Traffic Control Could Save CO2 Equivalent of Denmark's Economy.