OCTOBER 22, 2009
Building a Better Air-Traffic-Control System
By SCOTT MCCARTNEY
WSJ
When Air France Flight 447 crashed in the Atlantic Ocean in June, seven hours elapsed before air-traffic controllers realized it was missing, delaying search and rescue efforts and bewildering air travelers over how a jumbo jet could be lost in an age when even simple cellphones can pinpoint positions. Could it happen in the U.S. and other parts of the world? Thanks to a relatively new breed of air-traffic-control systems, that isn't likely. Air-traffic controllers in the U.S., Europe, Canada, Australia and New Zealand, who control most of the air traffic across oceans, now have modern satellite-based systems that include frequent automatic position reporting from airplanes and email-like communications between pilots and controllers.
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The Federal Aviation Administration's "NextGen" development program for the continental U.S. has a history of delays and failures. But it is now on track, according to government and industry groups, to produce in the next 10 years or so an air-traffic-control system with lots more capacity. With satellite-based data links instead of radar, which is somewhat slow and not precisely accurate, jets will be able to safely travel closer together, reducing delays. Faster communications over data links will allow controllers to handle more airplanes at one time. And with better computer systems that can predict conflicts far in advance, planes will get to pick their best route rather than be restricted to the set paths in the sky today. Systems to handle busy skies over land will be different from the oceanic system, but built with the same functions, communications and data links.
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The U.S. system, called Advanced Technology and Oceanic Procedures, or ATOP, was adapted by Lockheed Martin Corp. from a system developed in New Zealand (Australia's system was the other finalist). So far, ATOP has saved airlines 330,000 flying miles per year—as far as flying to the moon and half-way back—and nearly 10 million gallons of fuel. The system has been in use in the U.S. for four years. Data come from multiple sources on board aircraft, in case one fails, and multiple computers run together on the ground to provide backup. Planes report every 14 minutes, though controllers can change that to more frequent reporting, if necessary. If a position report is six minutes overdue, alarms go off. And the system automatically warns controllers if planes stray off course.
Controllers say the system is a huge improvement, but all the kinks haven't yet been worked out. ATOP gives them a radar-like picture of all planes in the section of oceanic air space they are responsible for, accurately showing position, direction, speed, assigned route and other information. Messages can be zapped back and forth with pilots. Any potential conflicts get automatically flagged to controllers as much as two hours before planes would get closer than separation standards allow. Problem flights are marked with flashing orange lines, and controllers have to take action to resolve conflicts before the lines go red 30 minutes before separation standards would be violated.
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Using ATOP, if a pilot requests an altitude or route change, the system loads the new information, based on the data transmission from the plane, calculates any possible conflicts and suggests responses from the controller automatically. If there aren't any problems with the request, approval can be sent with a couple of mouse clicks. And if any other flights are in the way of the requested new route, they get highlighted on the controller's screen in red.. Controllers can allow airlines to design their own flight paths instead of using one of the 16 routes drawn up each day by controllers in the U.S. and Japan. (These are the routes that—based on winds, temperatures and other factors—controllers think will be best for that day.) That flexibility allows them to optimize each flight's route, based on the latest wind and temperature reports (the colder it is, the more efficient a jet engine is).
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Not all planes across oceans have data-link capabilities, and high-frequency radio is still used with some flights and as a backup with others. Many aircraft also have satellite phones that controllers can call. And some nations, notably Brazil and Senegal, which were handling Air France Flight 447, don't yet have modern oceanic air-traffic-control systems. The Airbus A330 jet with 228 people aboard crashed on June 1 about 930 miles off the coast of Brazil. Senegal never took control of the jet from Brazil, and it wasn't until seven hours later that controllers in Madrid and Brest, France, raised an alarm, investigators said.
Printed in The Wall Street Journal, page D8
http://online.wsj.com/article/SB20001424052748703816204574487173981612780.html (subscription)
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