O'Hare Airport's primary radar system shut down twice Friday, delaying many flights at one of the nation's busiest airports.
O'Hare's Airport Surveillance Radar 9 first stopped operating about 3:30 a.m., said Wendy Abrams, spokeswoman for the Chicago Department of Aviation.
The radar was fixed at 9 a.m., but it went down again at 9:35 a.m. and was restored just before noon.
A pair of defective switches caused the outages, and the airport used a backup system in south suburban Tinley Park while Federal Aviation Administration technicians worked on the problem, officials said.
The airport has had only one on-site radar system for the last 12 years, though the FAA plans to install a second by 2008 as part of the O'Hare expansion project.
Delays on Friday averaged from 30 to 45 minutes for inbound and outbound flights, according to Abrams.
Ray Gibbons, of the National Air Traffic Controllers Association, said 96 planes usually arrive per hour at O'Hare, but that number was trimmed back to 60 because the backup radar system covers a smaller portion of O'Hare's airspace.
''The fact that O'Hare has only one radar site is absolutely ridiculous,'' Gibbons said.
'NOT OUR BEST . . . SCENARIO'
When the radar failed the second time, Gibbons said it took as long as five minutes for controllers to locate an inbound plane from Milwaukee after they switched to the backup system again.
"It's certainly not our best operating scenario," he said.
Midway Airport was not affected by Friday's outages because its radar system is at the Tinley Park facility.
The outages did, however, impact the Chicago Executive Airport in the northwest suburbs, and Waukegan Regional Airport in far north suburban Waukegan.
WORST O'HARE DEPARTURES
American Airlines Flight 1914 to Newark, 16 percent on time
Continental Airlines Flight 1162 to Newark, 17.4 percent
Mexicana Flight 801 to Mexico City, 20 percent
American Airlines Flight 1450 to Newark, 27.6 percent
American Airlines Flight 873 to Los Angeles, 27.6 percent
American Airlines Flight 336 to N.Y. La Guardia, 27.6 percent
United Airlines Flight 690 to La Guardia, 28 percent
Continental Airlines Flight 1174 to Newark, 28 percent
Executive Airlines Flight 324 to Norfolk, Va., 30 percent
US Airways Flight 1470 to Philadelphia, 30 percent
WORST MIDWAY DEPARTURES
AirTran Flight 635 to Newark, 17.9 percent on time
ATA Flight 4220 to New York La Guardia, 20.7 percent
ATA Flight 4208 to La Guardia, 26.7 percent
Continental Flight 1141 to Newark, 29.2 percent
Southwest Airlines Flight 260 to Detroit Metro Airport, 31 percent
Continental Flight 1147 to Newark, 34.8 percent
Southwest Airlines Flight 390 to Jackson, Miss., 36 percent
Southwest Airlines Flight 1734 to Phoenix, 37.5 percent
Southwest Airlines Flight 738 to Seattle, 39.1 percent
AirTran Flight 633 to Newark, 40 percent
There's something about Newark . . .
Air traffic controllers say flights to Newark are delayed so frequently because airlines schedule more flights in and out of the airport than it can handle.
News stories provided by third parties are not edited by "Site Publication" staff. For suggestions and comments, please click the Contact link at the bottom of this page.