Optimisation de routes aériennes

HK introduces shorter flight routes to help airlines save fuel
By Leithen Francis

Hong Kong's Civil Aviation Department (CAD) has shortened the flight routes to Hong Kong's airport which means aircraft arriving from Europe, China, the Middle East and southeast Asia save 14mins on the flight time.

The CAD says the new flight routes, developed with the help of satellite technology, allow aircraft to save about 210 kilometres or 14mins in flight-time.

The changes will take effect on 22 October and will apply to aircraft arriving from Europe, China, the Middle East and southeast Asia, it says, adding that the shorter flying time delivers fuel savings.

A map from the CAD shows the shorter routings have been achieved by allowing aircraft to stay closer to the China's coastline rather than flying so far out into the South China Sea.

Much remains to be done on the regulatory and technical side of achieving performance-based navigation, but airlines are discovering that they need to pay attention to the basics, especially local sensitivity to jet noise, when they implement it.

In PBN, the precision of satellite navigation allows an aircraft to take any route within a navigation network rather than being restricted to flying between beacons. The satellite-based navigation tools that are the backbone of PBN bring a “green” efficiency to the system by permitting more direct routing, closer spacing between enroute aircraft, and more precise descents and ascents. This efficiency translates into fuel savings, emission reductions and decreased airport noise (see p. 47).

PBN’s promise includes a 3-10% increase in airport capacity, 10% reduction in delays, 8-10% slice off fuel burn and 30% drop in overall noise patterns simply because it utilizes airspace more efficiently, GE Aviation Civil Systems President Chet Fuller told a gathering of airline, manufacturing and regulatory experts here last week at the annual Global PBN Summit.

The summit is normally dominated by technical discussions. But there was as much talk this year about the political practicalities of instituting PBN as about the finer points of aircraft sequencing, regulatory integration of U.S. and European navigation standards and the fuel efficiency of time-based aircraft separations.

Until some airline pioneers—starting with Seattle’s hometown Alaska Airlines—began implementing PBN’s optimized flight paths and quick descents to avoid fuel-wasting indirect routings, noise politics that roiled so many cities a decade or more ago had pretty much died down, notes Paul Dunholter, president of BridgeNet International, a consultancy helping carriers and airports implement PBN.

But even when new descents decrease jet traffic’s overall environmental footprint, they are likely to raise it for specific areas. When that happens, long-dormant airport noise opposition is quickly stirred. Cutting imports of foreign oil and reducing greenhouse gases may be laudable goals, but they are far more amorphous than the specifics of community noise.

“New noise is worth 100 dB. over old noise” in riling up opposition, says Airports Council International-North America senior adviser Dick Machi. “From the community standpoint, it’s always going to be about noise.”

As in the past, the noise debate revolves more around what are perceived to be high levels from commercial jets rather than the measurable noise residents may experience but fail to register from other urban sources. Jets are readily visible targets.

Airline executives are only too happy to plead guilty to forgetting lessons from the past. The environmental and efficiency improvements offered by PBN—Alaska labels its descent approaches for Seattle-Tacoma International Airport the “green valley”—seemed so obvious that many admit they failed to think about how the system is perceived by a public unfamiliar with the ins and outs of the technology.