More `ghost' aircraft at O'Hare


At least 10 more "ghost" images have appeared this week on radar scopes covering O'Hare Airport airspace, but federal officials said Wednesday they think the problem might be caused by new skyscrapers, cranes or large metallic objects that pierce the sky.

"I would attribute it to construction," said Gary Duffy, the FAA's airway facilities maintenance chief for the Chicago area.

Radar data from the Terminal Radar Approach Control center in Elgin has been shipped to a Federal Aviation Administration center in Atlantic City, N.J. Officials expect an analysis of that data--which should be done in a week or so--will confirm their theory.

"I wouldn't be surprised if there's a building where they just put a new metal roof on somewhere around here, and that's causing a reflection" of the radar's beacon beam, which in turn creates a false image, Duffy said.

Data from the Elgin facility Monday, when there were five ghosts, and Tuesday, when there were another five, has been sent to the FAA's William J. Hughes Technical Center in New Jersey, officials said.

The facility will search for whatever is causing the problems. And if the root is a physical structure, technicians can then tinker with the chips or software so that those ghosts don't appear in the future, Duffy said.

In the meantime, an FAA employee now has been stationed in the control room "so when these incidents occur, they can get right on them, get the data reduced and investigate it immediately," Duffy said. He said he's almost positive there is no problem with the software or the radar itself.

Mike Egan, vice president of the National Air Traffic Controllers Association local in the Elgin facility, which handles flights within a 40-mile radius of O'Hare, questioned that assertion.

"The problems continue to grow," he said. "And as far as I know, any time there's ghosting, it's a radar problem. The equipment should be able to filter it out."

The Chicago Sun-Times revealed Sunday that numerous ghost images have appeared recently, sometimes appearing on radar near real aircraft. That has caused controllers, in some instances, to order real airplanes to take quick, evasive action that was later determined to be unnecessary.