A full-blown war of high-tech noise detection is about to begin between a group of frustrated suburban officials and the City of Chicago.
It follows decades of skirmishes over decibel levels--suspect numbers in the eyes of some suburban officials--and continues to escalate as more and bigger passenger planes have roared out of O'Hare International Airport.
Until now the city held all the microphones and data recorders, telling noise-numbed suburbanites whose homes lay beneath O'Hare's flight paths that maybe it wasn't as loud as they thought.
But Monday, the anti-noise Suburban O'Hare Commission proudly wheeled out its own weapon in the battle: a Danish-engineered sound and flight-path detection system that will be owned and operated by the suburbs--but will be paid for by the City of Chicago.
The commission plans to install the system in six roving vans that can cruise to wherever residents complain of noise and monitor it over a period of days. The information then will be transmitted to the commission's offices.
"This is a beginning for us," said John Geils, mayor of Bensenville and chairman of the commission, which represents 11 suburbs. "We've been promoting noise-monitoring legislation for a decade in Springfield. Now we can look forward to bringing closure to the problem."
The cost of the system, estimated at between $500,000 and $600,000, will be borne by Chicago as part of its noise-reduction pact with the suburbs.
The noise debate goes back decades, but a key battle in the new fight will be over a 1993 city-drawn "contour" map showing the number of homes affected by noise from flights into and out of O'Hare. The commission says the noise contours are far larger than the city claims.
"The city's study is a 1993 study, and this is 1997," said Mayor Ted Sherwood of Des Plaines. But even in 1993, commission members did not agree with the dimensions of the city's noise map, he noted.
At stake is the cost of the city's program to soundproof homes and schools where the noise level is considered either an intolerable distraction or a nagging annoyance. The city is committed to soundproofing 4,500 homes to the north, west and south of O'Hare, at a cost of $234 million.
But a bigger noise contour could expand considerably the number of eligible homes and the city's cost.
"It means hundreds of millions of dollars more if Chicago meets its obligations," said Joseph Karaganis, the lawyer who represents the commission.
Last year, Karaganis won a $12.2 million noise abatement settlement from the city to soundproof schools in DuPage County.
The vans for the Suburban O'Hare Commission's new system aren't expected until sometime in April, and there wasn't much in the way of equipment to look at Monday other than a 25-foot microphone mast and a couple of laptop computers with colorful flight-path maps of the area.
But when it's all up and running, commission officials say they will be able to definitively measure aircraft noise within a 15-mile radius of O'Hare.
The system also will be able to read an aircraft's radar response to a Federal Aviation Administration signal.
This, said Art Benedict, a spokesman for Bruel & Kjaer, manufacturer of the monitoring system, will provide information about each airplane's flight path, the angle of ascent and the plane's call sign, which identifies the model of aircraft and the airline that owns it.
Meanwhile, in January, the City of Chicago's Department of Aviation set up a new $4 million noise-detection system with 22 monitors at fixed positions in 15 suburbs.
The data is transmitted to the O'Hare Noise Compatibility Commission, an agency created by the city.
The city's new system, which has not been officially dedicated yet, recently produced its first report, summing up airplane noise for the month of January, said Mary Rose Loney, commissioner of the city's Department of Aviation.
Loney said the city's new system will be able to identify each noise "event" by airline, flight path and flight number. And it will be directly linked to the FAA's radar system, she said.
But Karaganis argues that the city's system is limited because its monitoring devices are in fixed positions--attached to utility poles and buildings--and because the system averages the noise at each location over a 24-hour period.
"They fold in the quiet times with the very noisy times. Our equipment will allow us to measure the noisy times and the areas where Chicago says there isn't any noise," he said.
Loney, however, said the fixed position, 24-hour averaging is the method favored by the federal government.
"We use the criteria the federal government sets for us in defining a noise contour," said Loney. She added that the city has offered to have its data evaluated by an independent third party.
"That's how confident we are in ourselves," she said.