United readies for last Aspire flight of 2008

Washington DC
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While a United Airlines Boeing 747-400 flight from Sydney to San Francisco on 14 November concludes "fuel-optimized" demonstrations in 2008 for the Asia and South Pacific Initiative to Reduce Emissions (ASPIRE), regulators would like to see further participation starting in the third quarter next year.

FAA, Airservices Australia and Air New Zealand signed on to ASPIRE in February in a move designed to accelerate the development of air traffic control (ATC) procedures that reduce aviation's environmental footprint.

FAA has since spoken with northern and western Pacific service providers and Asian flag carriers about joining the ASPIRE partnership, which will likely expand during the next 11 months, an FAA spokesman says.

An ASPIRE annual report will be published during the second quarter next year and more demonstration flights may follow as early as the third quarter, the spokesman says.

As part of the process, United's flight data will be analysed along with results from Air New Zealand (ANZ) and Qantas, which participated in similar demonstrations on 12 September and 22 October.

ANZ's 777 flight from Auckland to San Francisco burned 1,200 USgal (4,542 litres) less fuel and emitted 11t less carbon monoxide than normal.

If ideal weather conditions prevail during United's flight, the US major says it expects to save as much as 2,000 USgal (7,570 litres) of fuel. These optimal figures translate to 5%-6% savings from a normal Sydney-San Francisco flight, a United spokesman says. Overall, United would expect to see 10% to 15% reductions from normal if NextGen technology is applied across US ATC, he says.

As happened with ANZ and Qantas, United will receive priority clearance from ATC for taxiing and departure to help achieve savings. In addition, the airline will have access to restricted airspace outside of Sydney and possibly en route, the United spokesman says.

Obviously, every flight cannot receive priority taxiing and departure, but the purpose of the fuel optimized flight is to demonstrate the savings that would occur if there were no delays, and with ATC modernization, there would be reduced delays, he says.

Upon reaching cruising altitude, United will reroute the flight by taking advantage of updated weather data, including information such as tailwinds, which might be more optimal on a different path or different altitude, says United's spokesman, explaining that technology in the cockpit and technology at ATC will allow for more analysis of conditions, enabling a faster approval process for inflight changes.

Inflight rerouting is not usually available, he says. "The process of getting that approval to reroute is manual and it's not able to be approved as often as we like. So, we're not able to take advantage of new weather data," the spokesman explains.

Roughly 66% of fuel and emissions savings will occur at cruising altitude by flying at the optimal altitude and the user preferred route, assuming optimal savings are achieved, the United spokesman says. Instead of following a flight path developed months ago, the aircraft will follow a path determined by data collected within two hours of takeoff, in addition to rerouting inflight.

United will also use a tailored arrival instead of a step-down approach. The tailored arrival alone is expected to save up to 400lb (180kg) of fuel, United says.

After landing, the airline will calculate and publish actual savings.