In order to lend some clarity and background to the on-going media discussion (as a result of the tragic accident involving SWA 1248 at Chicago's Midway airport) of the nation's elder airports and shorter runways, the following FAA Data Sheet on EMAS is presented for your education...

Background

The Federal Aviation Administration (FAA) requires that commercial airports, regulated under Part 139 safety rules, have a standard Runway Safety Area (RSA) where possible. At most commercial airports the standard RSA is 500 feet wide and extends 1000 feet beyond each end of the runway. The FAA has this requirement in the event that an aircraft overruns, undershoots, or veers off the side of the runway. The most dangerous of these incidents are overruns, but since many airports were built before the 1000-foot extension was adopted some 20 years ago, the area beyond the end of the runway is where many airports cannot achieve the full standard RSA. This is due to obstacles such as bodies of water, highways, railroads and populated areas or severe drop-off of terrain.

The FAA has a high-priority program to enhance safety by upgrading the RSAs at commercial airports and provide federal funding to support those upgrades. However, it still may not be practical for some airports to achieve the standard RSA. The FAA, knowing that it would be difficult to achieve a standard RSA at every airport, began conducting research in the 1990s to determine how to ensure maximum safety at airports where the full RSA cannot be obtained. Working in concert with the University of Dayton, the Port Authority of New York and New Jersey, and the Engineered Arresting Systems Corporation (ESCO) of Ashton, PA, a new technology emerged to provide an added measure of safety. An Engineered Materials Arresting System (EMAS) uses materials of closely controlled strength and density placed at the end of a runway to stop or greatly slow an aircraft that overruns the runway. The best material found to date is a lightweight, crushable concrete. When an aircraft rolls into an EMAS arrestor bed, the tires of the aircraft sink into the light concrete and the aircraft is decelerated by having to roll through the material.

Benefits of the EMAS Technology

The EMAS technology provides safety benefits in cases where land is not available or where it would be very expensive for the airport sponsor to buy the land off the end of the runway.

The EMAS technology also provides an added measure of safety at airports where it is not possible to have the standard 1,000-foot overrun. This technology is now in place at 14 airports with installation under contract at four additional airports.

A standard EMAS installation extends 600 feet from the end of the runway. An EMAS arrestor bed can still be installed to help slow or stop an aircraft that overruns the runway, even if less than 600 feet of land is available.

The Office of Airports plans to conclude its RSA inventory of runways at the approximately 575 commercial airports by the end of 2005. This inventory will allow the agency to determine which airports can benefit from the EMAS technology and to direct federal funds to RSA upgrades at those airports.

Presently, the system using crushable concrete is the only system that meets the FAA standard.

EMAS Arrestments

To date, there have been three incidents where the technology has worked successfully to keep aircraft from overrunning the runway and in several cases has prevented injury to passengers and damage to the aircraft:

• May 1999: A Saab 340 commuter aircraft overran the runway at JFK
• May 2003: Gemini Cargo MD-11 was safely decelerated at JFK
• January 2005: A Boeing 747 overran the runway at JFK

EMAS Installations

Currently, EMAS is installed at 18 runway ends at 14 airports in the United States. With plans to install four additional EMAS systems at four more airports.

FMI: www.faa.gov