November 30, 2006   Southwest News-Herald - City

Buffer Zone Installed at Midway

Crushable Concrete Replaces Fence Along 55th and Central

As the first anniversary of a fatal runway accident at Midway Airport approaches, a crushable concrete

 safety zone was installed last week on the same runway in an effort to prevent future such accidents from occurring.

A 6-year-old Indiana boy was killed Dec. 8, 2005, when a Southwest Airlines jet slid off a slick Runway 31 Center during a snowstorm and broke through a fence onto Central Avenue near 55th Street.

The aircraft struck several cars, including the one the boy was traveling in with his family, who had come to Chicago to visit relatives.

That was the first accident of its kind at the airport, and the first fatality in Southwest’s 35-year history.

But after it happened, the Federal Aviation Administration gave the Chicago Department of Aviation a $15 million grant to pay for improvements to the runways, which due to the compact nature of the airport, come closer to the boundary fences than those at most airports.

“Our goal was always to complete the (arrester bed project) on Runway 31C before the end of this year. And thankfully, it came in on budget and ahead of schedule,” said Wendy Abrams, spokes-person for the Chicago Department of Aviation this week.


Originally, it was thought that the crushable concrete material  produced by Engineering Arresting Systems Corp., would not be suitable for Midway because the limited space available would mean that the crushable concrete would be so close to taxiing planes that it would be damaged by the jet blasts coming from the engines.

“Keep in mind that jet blasts can be as strong as Category 5 winds,” said Abrams, referring to the winds exceeding 155 mph winds that define the most severe hurricanes.

To prevent that damage, Abrams said a polymer coating was added to the blocks to make them sturdier.

“In other words, the manufacturer improved the technology to make it work here,” said Abrams.

The coated blocks were first tried out successfully at LaGuardia Airport, in New York, where the runways are adjacent to Flushing Bay.

A National Transportation Safety Board investigation determined that if it had been in place at Midway, the aircraft-arresting system would likely have prevented the accident last December.

The 170-foot long arrester bed is currently made up of 1,764 16 sq. ft. blocks made of water, foam and cement.

Abrams said 10 more rows of blocks are expected to be added as soon as the FAA relocates the runway localizer antennae pilots use to center aircraft on the runway when they land. When it is completed,   the arrester bed will measure 245 feet long.

The arrester bed is built on a slight incline, gradually rising from 7 inches to 21 inches in height when the project is completed. The total cost of the 31C runway project was $6 million, according to Abrams.

“As soon as the next FAA grant comes through, three more arrester beds will be built in the other runways at the airport, in the hope of completing the entire project by next year,” said Abrams this week.

Studies done by the FAA have been shown that the compact arrester beds being installed at Midway  would be able to stop a plane moving at 40 knots, or 46.1 mph,

The agency has said that about half of the runway-overrun incidents in the United States involve speeds of less than 40 knots. At larger airports, with more space available, 600-foot arrester beds are being installed that are capable stopping planes traveling up to 70 knots (80.6 miles per hour.

The family of the boy who died in the crash last year filed suit against Southwest Airlines and the FAA, as did several passengers who were on the aircraft at the time. The status of those lawsuits could not be determined at press time.

from this link