Sunday, September 27, 2015

'Ghost planes' display aid at O'Hare helping safety, capacity problems

"Ghost" images of planes landing at O'Hare are helping air-traffic controllers to more safely stagger jets operating on converging flight paths.

"Ghost" images of planes landing at O'Hare International Airport are helping air-traffic controllers safely stagger jets on converging flight paths in the crowded airspace near the airfield, according to the Federal Aviation Administration.

The ghost planes are also helping restore some of the efficiency that was lost last year when safeguards were introduced at O'Hare to reduce the chance for a collision on converging flight paths, officials said.

The potentially deadly traffic intersection in the sky is less than 1 mile from the ends of two runways — one for arrivals, the other for departures. Last year, the FAA prohibited the specific runway combination during the busiest daytime hours, when planes are taking off or landing roughly every 20 seconds, until a better plan came along.

The two runways themselves do not physically intersect, but planes could cross flight paths under one scenario:

A plane cleared by O'Hare tower for takeoff on diagonal runway 32 Left, which points to the northwest, could fly too close to or even hit or be struck by a plane landing toward the west on east-west runway 27 Right if, instead of completing the landing, the pilot of the plane needed to execute an unplanned go-around procedure.

Last year, to eliminate the possibility of a close call or an even worse outcome, the FAA banned planes during the day from landing on 27 Right while other planes were taking off on 32 Left.

The move was part of a national strategy to improve the safety of converging runway operations at a number of major airline hubs. The change was recommended by the National Transportation Safety Board in response to some near midair collisions, including a 2006 incident involving a United Airlines plane and an American Airlines plane at McCarran International Airport in Las Vegas.

An automated tool that was recently introduced at O'Hare provides visual guidance to air-traffic controllers to space two planes involved in a converging runway operation more than 1 1/2 miles apart from the critical intersection point, officials said.

Called the Converging Runway Display Aid, the computer program creates a ghost aircraft in a window on the controller's screen, said Paul Litke, the FAA's air-traffic manager for the Lake Effect District and a former controller and manager at O'Hare tower. The ghost plane's final approach to land on 27 Right matches an actual aircraft flying to the runway.

The display aid calculates a safe gap between the arriving and departing planes. If either a ghost aircraft or a real aircraft is in the runway 27 Right window, the controller must hold the plane that is lined up to depart on 32 Left until the all-clear is given, Litke said.

The computer program maximizes safety and the rate of takeoffs and landings, Litke said.

"It allows us to use this departure runway (32 Left) again, which we haven't been able to do for more than a year," Litke said. "We are still learning, and it will take some time" to use the converging runway automation to its full potential, he said.

The Converging Runway Display Aid, which since July is being phased into O'Hare's operations, has resulted in an increased number of daytime departures on 32 Left over the past few months, as well as on diagonal runway 4 Left, which points to the northeast and also has a flight path that converges with the flight path of 27 Right arrivals, FAA spokesman Tony Molinaro said.

The increased use of the diagonals has produced a small side benefit to some of O'Hare's noise-weary neighbors who live east and west of the airport. For much of the summer, before the display aid was activated, daytime departures from 32 Left were near zero, according to data provided by the Chicago Department of Aviation. Currently, five to 10 flights per day, or 200 to 300 per month, depart 32 Left during the day, the FAA said. In addition, about 200 daytime flights depart runway 4 Left monthly.

Although the numbers are small in comparison to the roughly 2,500 takeoffs and landings each weekday at O'Hare, "those (32 Left) departures occur during the busiest hours, so they are very effective in taking pressure off" of the airport, Molinaro said.

Runway 32 Left is scheduled to close in 2019, when the sixth east-west parallel runway is set to open under the city's O'Hare expansion plans. The primary goals of the runway project include increasing O'Hare's capacity while reducing flight delays, and improving safety by eliminating runways that either physically intersect or that have converging flight paths. The fifth east-west parallel is scheduled to open Oct. 15.

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