Tug of awe

摘要

The challenge to drive down CO_2 emissions in the aerospace industry has seen billions of pounds spent on smart materials, fuel cells and improvements in engine design. However, up until now, little work has been carried out on one of the most promising areas of carbon reduction in aircraft flight - the taxiing phase.rnAccording to Airbus, taxiing its aircraft between the main gate and the runway-produces around 18m tonnes of CO_2 per year and is estimated to cost airlines in the region of $7bn-8bn (£4.2bn-4.8bn). It is also a source of foreign-object debris, resulting in around $350m worth of aircraft maintenance and flight delays each year.rnThese figures are rising alongside increasing airport traffic. Currently, an aircraft can take anything between 45 minutes to two hours to leave the ground, during which time it is running its main propulsion jet engines and burning one tonne of fuel for every 17 minutes that it remains idle.