Feb. 2--A safety improvement that will guide pilots to land in bad weather on two runways at O'Hare International Airport has been delayed while authorities make sure light poles, traffic signals and trees bordering the airfield do not block the new equipment's communication with planes, officials said Wednesday.
The new instrument landing approach system was first recommended for O'Hare in 1991 to help reduce serious flight delays in bad weather.
The U.S. Department of Transportation provided $5.5 million in funding in 2004, and the system was originally scheduled to begin operating in November 2005, according to the Chicago Department of Aviation.
After changes that set back the project several months, the enhanced navigation aids were supposed to begin working in January on two parallel runways, 27 Left and 27 Right, that are used by planes landing from the east.
But discrepancies surfaced over ground obstructions found in separate land surveys conducted by the Federal Aviation Administration and the city.
The city will lower some light poles as much as 8 feet on Bessie Coleman Drive, reduce the height of traffic signals by about a foot and trim or remove some trees over the next month, said FAA spokeswoman Elizabeth Isham Cory. She said the changes, which the city planned as part of expanding O'Hare's runways, have not delayed the start up of the bad-weather landing system.
Use of the landing system will allow O'Hare to accept more arrivals each hour during bad weather. The airlines schedule up to 100 arrivals an hour, but sometimes as few as 65 can be accommodated when visibility plummets and forces air-traffic controllers to close some runways.
Cory said the FAA is still waiting for the city to provide documents certifying the accuracy of its land survey, which showed the obstructions. The new landing system will then be commissioned, she said.
The city gave the FAA the data it requested two weeks ago, and a survey certification letter will be sent to the federal agency soon, said Roderick Drew, spokesman for the city's O'Hare Modernization Program.
Two of O'Hare's existing six runways are equipped with the bad-weather landing system, which automatically communicates with aircraft and guides planes to the ground in dense fog or snow, even when pilots cannot see the runway until a few seconds before the wheels touch the pavement.
The two runways already outfitted with the system, 14 Left and 14 Right, are to be demolished under Chicago's plan to reconfigure the airfield.
The system allows planes to land even when clouds are as low as 100 feet above the runway and visibility outside the cockpit is only 600 feet, according to the FAA. Today, clouds must be a minimum of 200 feet above the ground and visibility must be 1,800 feet on the pair of runways being improved.
Chicago aviation officials like to point to the 31-year-old airport in Dallas as a proven model for the parallel runways envisioned at the future O'Hare International Airport.
The upgrade announced by Federal Aviation Administration officials on Tuesday will help steer pilots toward runways at one of the busiest U.S. airports even when severe weather hampers visibility.
Chicago has promised that its $14.7 billion plan virtually will eliminate late and canceled flights during bad weather.