Alaska Airlines Boeing 737-790 WL N607AS (msn 29751) SEA (Bruce Drum), originally uploaded by Airliners Gallery.

Alaska Airlines (Seattle/Tacoma) this week demonstrated next-generation flight procedures during a test flight over Puget Sound that burned less fuel and reduced emissions by 35 percent compared to a conventional landing. The flight was part of Alaska Air Group’s “Greener Skies” project at Seattle-Tacoma International Airport (Sea-Tac) focused on using satellite-based guidance technology pioneered by Alaska Airlines to fly more efficient landing procedures that will reduce environmental impacts in the Puget Sound region. The airline, in cooperation with the Port of Seattle, Boeing and other airlines serving Sea-Tac, is seeking Federal Aviation Administration (FAA) approval for the procedures, which could ultimately be used by all properly equipped carriers at Sea-Tac.

Testing for the project began last summer and, since then, Alaska Airlines has flown two other demonstration flights and submitted more than half of the proposed procedures for FAA review. Representatives from Alaska, Boeing, the FAA and the Port of Seattle participated in the most recent demonstration to observe the level of flight path precision and fuel consumption on eight landing approaches in a Boeing 737-700. With a landing weight similar to a typical passenger flight, the shorter and more efficient approaches reduced carbon emissions and saved 400 pounds of fuel per approach.

The test flight used satellite guidance technology called Required Navigation Performance (RNP) to fly more direct, continuous descent approaches. Alaska Airlines estimates the new procedures at Sea-Tac will cut fuel consumption by 2.1 million gallons annually and reduce carbon emissions by 22,000 metric tons, the equivalent of taking 4,100 cars off the road every year. They will also reduce overflight noise for an estimated 750,000 people living below the affected flight corridor.

Typically, commercial aircraft follow a lengthy approach pattern and series of stair-step descents before landing. Using RNP technology and a continuous descent, also called an optimized profile descent (OPD), aircraft can descend from cruise altitude to an airport runway along a shorter, more direct flight path at low power.

Planning and testing of the procedures will continue through the remainder of the year and will be integrated into Alaska Airlines and sister carrier Horizon Air’s commercial operations at Sea-Tac pending FAA approval.

Alaska Airlines pioneered RNP precision flight-guidance technology during the mid-1990s to help its planes land at some of the world’s most remote and geographically challenging airports in the state of Alaska. RNP provides computer-plotted landing paths by using a combination of onboard navigation technology and the global positioning system (GPS) satellite network. It improves safety and reliability in all weather, and reduces reliance on ground-based navigation aids. Alaska Airlines currently uses FAA-approved RNP procedures at 23 U.S. airports.

Alaska Airlines is the only major U.S. air carrier with a completely RNP-equipped fleet and fully trained crews. Alaska is also the first airline approved by the FAA to conduct its own RNP flight validation. Horizon Air’s fleet will be fully RNP-equipped by the end of 2011.

RNP and OPD are part of the Next Generation Air Transportation System, the FAA’s plan to modernize the National Airspace System through 2025. This initiative will increase airspace capacity and efficiency while improving safety and reducing environmental impacts through the replacement of legacy ground-based equipment with new satellite-based technology and aircraft navigation capabilities.

As part of the initial Alaska Airlines RNP operational approval team, Boeing began installing RNP guidance technology on its aircraft in 1994. Currently, all Boeing production airplanes are RNP-capable, and solutions are available to upgrade the in-service fleet. The Boeing Company is continuing this pioneering tradition by working with Alaska Airlines, the FAA and the Port of Seattle in implementing RNP solutions and the Greener Skies program for Sea-Tac.

Copyright Photo: Bruce Drum. Boeing 737-790 N607AS (msn 29751) holds for departure clearance at Sea-Tac.