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Sunday, June 29, 2008 By DENIS PAISTE MANCHESTER
– One of the newest safety features at Manchester-Boston Regional
Airport will never be airborne. The Engineered Material Arresting System
(EMAS) installed at the end of the airport's secondary runway is a checkerboard
of compressible concrete blocks that can slow and stop an aircraft that
overshoots the runway. EMAS systems have successfully arrested the
errant paths of aircraft that overran U.S. runways at least four times from May
1999 through July 2006, preventing injury to passengers or damage to aircraft,
according to the Federal Aviation Administration. Three of the incidents were
at New York's John F. Kennedy International Airport, while one was at
Greenville, S.C. In this photo provided by
the Port Authority of New York and New Jersey, the nose gear of the FAA test
jet is embedded in the concrete after coming to a stop in the EMAS at JFK. "It's a proven technology that has
demonstrated its ability to stop aircraft when they overshoot the runway,"
said Federal Aviation Administration spokesman Jim Peters. Manchester's system has been operational
since last November, but the last pieces of construction related to the project
were completed this spring, and a new airport service road around the EMAS
system has recently opened. The EMAS system is within the fenced area
just off of South Willow Street above Harvey Road at the departure end of the
runway. "We hope it never gets used,"
Manchester airport Deputy Director J. Brian O'Neill said. "When an aircraft rolls into an EMAS
arrestor bed, the tires of the aircraft sink into the lightweight concrete, and
the aircraft is decelerated by having to roll through the material,"
according to an FAA fact sheet. As the aircraft travels into the bed, the
three-foot square blocks get higher. The porous, or pelletized, concrete blocks
are designed to crush under the weight of the aircraft. That means whatever blocks are damaged during
the stop have to be pulled out and replaced. "It's expensive to replace,"
O'Neill said. The total project cost was $24 million, of
which the 150-foot by 300-foot concrete EMAS bed itself cost $3.5 million. The
EMAS bed covers an area about the size of a football field. Land acquisition,
design and other construction costs are included in the total, which was funded
by the FAA, state and local governments. The FAA contributed $16.1 million. Intersections with South Willow Street at
both Harvey Road and Perimeter Road were rebuilt as part of the project. A new
southbound lane added to the Harvey Road/South Willow intersection improves
southbound traffic flow near the Triangle Mall, O'Neill said. A navigational
aid that helps pilots touch down at the right spot also was relocated. At Manchester-Boston Regional Airport, the
EMAS surface is at the end of Runway 6, behind Thomas Malafronte, assistant
airport director-Air Service Development and Marketing. (DAVID LANE) FAA safety rules require runway safety areas
to be 1,000 feet, unless an alternative such as EMAS is used. The EMAS system
allowed the Manchester airport to have a 600-foot overrun area on Runway 6-24,
as the secondary runway is known. With the EMAS system in place, the total
overrun area is 900 feet long by 500 feet wide. Runway 6-24 is a cross-wind runway and is
used for about 25 to 30 percent of the airport's takeoffs and landings. "Aircraft land and take off into the
wind, so as you have a front go through and the wind changes, the air traffic
control tower will authorize you to take off or land," airport Director
Mark P. Brewer said. O'Neill said an additional benefit of having
the safety area on the cross-wind runway is spreading aircraft activity over a
larger area. Before the improvements were made to the runway, 99 percent of
aircraft activity impacted either Manchester or Londonderry. Because of the availability of the secondary
runway, more aircraft can take off or land using flight paths over Bedford and
Auburn. "So," O'Neill said, "no one
community is disproportionately burdened with aircraft activity." The airport has an unofficial goal of
splitting the runway activity 65 percent on the main runway and 35 percent on
the secondary runway, Brewer said. Thomas J. Malafronte, assistant airport
director for Air Service Development and Marketing, said the EMAS system also
works for planes that land short of the runway. While the runway improvements don't increase
airport capacity, they do enhance safety, O'Neill said. The new service road,
for example, means fuel trucks won't have to cross runways anymore, eliminating
a potential hazard. The safety area project involved 15,000 tons
of asphalt and 280,000 cubic yards of fill. The runway names, 6-24 for the secondary and
17-35 for the main, refer to compass headings, with 6-24 referring to 60
degrees and 240 degrees and 17-35 referring to 170 degrees and 350 degrees. The
main runway is nearly on a north-south alignment. |
