For Immediate Release
Release No. AWP5-0404
October 26, 2004
Contact: Donn Walker
Phone: (310) 725-3580
SAN FRANCISCO — The U.S. Department of Transportation’s Federal Aviation Administration (FAA) today started using a new landing procedure that will help cut delays at San Francisco International Airport. Known as the Simultaneous Offset Instrument Approach (SOIA), this procedure will allow up to a 25 percent increase in the number of arrivals during overcast conditions that frequently blanket the Bay Area.
"SOIA spells relief for the traveler," said FAA Administrator Marion C. Blakey. "This new procedure helps planes cut safely through the fog. It's going to keep air traffic moving."
The landing procedure takes advantage of an advanced radar system installed last year that is nearly five times faster than conventional airport radar. Because air traffic controllers can get a much more precise fix on approaching aircraft, two arriving planes are now able to fly above and then through the clouds at different angles while maintaining safe separation standards required during overcast conditions. Once the aircraft are under the cloud deck, the planes then fly a visual, parallel approach to the airport's two runways.
Before SOIA was implemented, San Francisco's two parallel runways were considered too close – 750 feet apart – for safe simultaneous landings during overcast weather. As a result, the arrival rate would drop from about 60 to 65 aircraft per hour during clear weather to about 30 to 35 aircraft per hour in overcast conditions, when only one runway could be used at a time. When in effect, SOIA will allow an extra six to eight aircraft to land each hour during overcast conditions, appreciably reducing delays caused by weather.
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New Approach at SFO
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The FAA expects SOIA to be used about 30 to 40 days a year, generally in the summer and fall when weather conditions cause clouds and fog along the coast. The approach will be used when the cloud ceiling is between 2,100 feet and 3,500 feet above the ground.
SOIA was developed through the close cooperation of the FAA and its air traffic controllers, San Francisco International Airport, pilots, and the airlines serving the airport.