Manchester-Boston Regional Airport

Manchester-Boston Regional Airport Blocks of a special lightweight concrete mixed with foam and air are placed to create a barrier for unaway planes.

An increasing number of airports across the U.S. and other countries are installing lightweight concrete barriers on their runways as safety nets for airplanes. Now a decade old, the evolving Engineered Materials Arresting System (EMAS) is at a point where its manufacturer claims it is virtually maintenance-free.

EMAS consists of 4-ft x 4-ft blocks of lightweight concrete mixed with a foaming agent and air that are placed at the edge of a runway, tapering in height to form a squarish bed. After an airplane skidded off a runway at John F. Kennedy International Airport and into the water in the mid-1980s, the Federal Aviation Administration and JFK operator Port Authority of New York and New Jersey began investigating passive arresting systems, says Rick Marinelli, FAA airport engineering manager. The agencies worked with Engineered Arresting Systems Corp., Logan Township, N.J., a division of France’s Zodiac Group, and began testing systems at JFK and LaGuardia Airports in the mid-1990s.

“We’re now on our third-generation version ”after $10 million in research and development, says Kevin Quan, senior regional director for ESCO. The second generation was more resistant to jet blasts but had to be repainted for water resistance every three to five years, he says. The blocks now only require inspection of joint sealants every few months. Marinelli says the product’s greater density now allows it to be be driven on by rescue and firefighting vehicles. Snowplows will still get stuck.

Since 1996, the system has successfully stopped five planes three at JFK. Quan says a Boeing 747 was “leaving the runway at close to 80 miles per hour” during a 2005 winter storm. “The bed stopped it before it went into the [bay].”

FAA in 2004 issued a new policy allowing an airport to have just 600 ft instead of 1,000 ft of safety area at the end of a runway if an EMAS was installed. That prompted a number of new installations, including two at Chicago’s O’Hare International Airport, says Quan. To date, 26 domestic and four international systems [in China and Spain] have been installed. Each installation is customized for the specific needs of each airport.

One of the most recent installations was at Manchester-Boston Regional Airport. The $3.5-million EMAS installation is part of a $13.5-million job held by Continental Paving Inc., Londonberry, N.H., to relocate and extend a runway to 7,650 ft, says Richard Fixler, the airport’s assistant director for engineering and planning.

The 170-ft x 300-ft barrier consists of 3,188 blocks varying from 6 in. to 26 in. in height, he says. Crews laid out a grid pattern to mark the locations. Installation took about a week. Blocks are calked in place with a silicon-based adhesive. The system allowed the extended runway to comply with FAA criteria and saved six acres of wetlands because the safety area did not have to extend to 1,000 ft, notes Fixler.

ESCO is the only manufacturer right now but Marinelli says FAA is soliciting ideas for other alternatives. “It’s a significant investment and ESCO is the only one making it at this point,” he says.