System Loses Effectiveness In Snowy Weather

A new ground-control radar system now in place at Chicago's O'Hare International Airport is drawing fire from the local president of the National Air Traffic Controllers Association, who says the technology meant to prevent runway incursions is notoriously inaccurate when snow is falling.

Joseph Bellino, NATCA's facility president at O'Hare, says the airport's new Airport Surface Detection Equipment (ASDE-X) often fails to detect snowplows, baggage carts and other vehicles.

"When we say 'cleared to land,' we're saying that runway is clear of all obstructions on the runway. If it's snowing, we say it, but we're keeping our fingers crossed," he told The Associated Press.

Not surprisingly, FAA officials say the situation isn't nearly as bad as NATCA makes it out to be. Agency spokesman Tony Molinaro says it usually takes a year to fine-tune a new system to account for differences in airport layout, and prevailing weather conditions. He added ASDE-X -- installed at ORD since July -- should be considered a "secondary tool," used to supplement controllers' eyes and communications with pilots.

"The controllers union leadership shouldn't be trying to scare the public," Molinaro said, adding the system is far better than the old ground radar once used at O'Hare, which often produced false or dual images in heavy rain.

The FAA acknowledges the system at O'Hare still has some bugs. During a heavy snowfall earlier this month, ASDE-X had trouble distinguishing snowplows, and other ground operations at O'Hare.

ASDE-X was first installed in Milwaukee in 2003. Today, the system is in use at 11 airports, with plans to increase that number to 35 by 2011. The system is also in used at Louisville International Airport... and Jeff Gilde, the local NATCA president, says ASDE-X has been problematic there, too.

On the eve of last year's Kentucky Derby, Gilde says, a heavy rain "made the system go completely blank, and it did not come back up."

"Basically, the tower visibility was zero. So we could not see out the window and we could not see anybody on radar," he added. "And we actually had an aircraft cross in front of another aircraft that was landing."

Gilde adds most of the system's initial bugs have since been corrected, though false warnings still result in go-arounds for airplanes on approach once every couple weeks. "For a safety system to be 100 percent effective, it should work 100 percent of the time, and this does not," Gilde said.

The FAA is looking into equipping ground vehicles with basic transponders, in order to provide clearer signals to ASDE-X receivers.

FMI: www.natca.org, www.faa.gov, www.ohare.com