After two of the remaining four diagonal runways at O'Hare close later this month, the airport is planning to experiment with alternate landing runways to reduce noise:
The city has developed a concept to rotate the designated "fly quiet'' runways at night to abate noise. Instead of planes flying over the same air corridors night after night, the rotation of runways — on possibly a weekly basis — would move the worst noise impacts from one community to another, aviation officials said.
The experiment would start, pending FAA approval, after diagonal runway 32 Right closes Aug. 20, officials said. Diagonal runway 32 Left, which is scheduled to close in 2019, would be among the runways used in the rotation during the interim, officials said, adding that numerous runway combinations might be applicable to help spread out the noise.
Only one arrival runway and one departure runway are needed nightly, officials said.
Even when only east-west runways are used late at night, air-traffic controllers will be asked to direct pilots to make turns when they reach the appropriate altitude after takeoff so that noise isn't restricted to communities east and west of O'Hare, officials said.
Runways 32R and 22L are hardly ever used anymore, so the closure won't really change current operations at O'Hare. But the opening of 28L at the south end of the airport will give visitors to Chicago an extra 15 minutes of taxi time, just like 27R provides.
At least it will be a little quieter in some of the adjacent suburbs. Sometimes.