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Analyzing the bearing capacity of materials used in arresting systems as a suitable risk mitigation strategy for runway excursions in landlocked aerodromes
Published in Inge Hoff, Helge Mork, Rabbira Saba, Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1, 2021
M. Ketabdari, E. Toraldo, M. Crispino
EMAS is defined as a bed of pre-cast blocks, consisting of FAA-approved materials, that is placed at the area after runway end threshold to decelerate an overrunning aircraft in an emergency. No external energy source is required for this system since it is a passive mitigation action. These blocks will predictably crush under the weight of an aircraft to provide one gentle aircraft deceleration. Drag forces develop at the tire-arrestor material interface to decelerate the aircraft. The successful deceleration reduces stopping distance considerably. An EMAS is positioned within the RESA set back area that is located after the runway end border and this setback length protects the arrestor bed from the aircraft intrusion during an under shoot, a short overrun, or material degradation due to jet blast.
Developing an anisotropic material for Engineered Material Arresting System (EMAS) usage
Published in International Journal of Pavement Engineering, 2021
Elvis A. Castillo-Camarena, Ernie Heymsfield
The FAA requires EMAS materials to be consistent in strength, durability, and sufficiently strong to enable aircraft control during an overrun event (FAA 2012). Aircraft rescue and firefighting (ARFF) equipment and maintenance vehicles must be able to travel on the EMAS bed without generating significant material deformation. An EMAS consists of a crushable material bed located at the end of a runway within the runway safety area. The EMAS is positioned on top of the runway pavement surface. An aircraft enters an EMAS during an overrun event when it is unable to completely stop within the setback length from the runway threshold. An EMAS is a passive system, no external supply energy is required to operate the EMAS system. As the aircraft moves through the EMAS, an interface develops between the penetrating aircraft tires and the uncrushed EMAS material. Vertical material force at the EMAS-tire interface supports the aircraft weight, and the horizontal material force, drag force, at the EMAS-tire interface decelerates the aircraft. The FAA specifies EMAS design and installation requirements in Advisory Circular (AC) 150/5220-22B (FAA 2012). AC 150/5220-22B defines an EMAS as ‘high energy absorbing materials of selected strength, which will reliably and predictably deform under the weight of an aircraft’. The EMAS design life is assumed to be 20 years.
Investigating the potential of using glass foam for an EMAS material to mitigate aircraft overrun accidents
Published in International Journal of Pavement Engineering, 2021
In an effort to ensure passenger safety during an aircraft overrun, the Federal Aviation Administration (FAA) requires a 305 m (1000-ft) runway safety area beyond the runway design end (FAA 2012). However, many airports are prevented from satisfying this requirement because of natural or man-made barriers. For these cases, the FAA allows for a reduced runway safety area length if an airport installs an engineered materials arresting system (EMAS). An EMAS is a passive energy system and therefore, does not use an external energy source for aircraft deceleration. The EMAS is designed to decelerate an aircraft to stoppage through drag forces developed from pressure exerted by the EMAS on the aircraft tires as the aircraft moves through the EMAS. An EMAS is designed to decelerate an aircraft without jeopardizing passenger safety and without causing aircraft structural damage. There are only two companies, Zodiac Aerospace and Runway Safe, that manufacturer an EMAS material that meets the FAA requirements included in AC 150-5220-22B, ‘Engineered Materials Arresting Systems for Aircraft Overruns’ (FAA 2012). Zodiac Aerospace is by far the largest manufacturer of EMAS. The Zodiac Aerospace product, EMASMAX, is installed at 109 runway ends at 67 U.S. airports (FAA 2018). In addition, EMASMAX is installed at 7 runway ends at 4 foreign airport locations (Zodiac 2017). In comparison, Runway Safe is installed at 4 runway ends at the Chicago Midway Airport. Preliminary estimates for EMAS cost can be approximated using the guidelines in FAA Order 5200.9 (FAA 2004). Unit costs in 2004 dollars are $150/m2 ($14/ft2) for site preparation and $840 /m2 ($78/ft2) for the EMAS bed installation. A recent Business Wire article predicts that the EMAS market will grow from $810.6 million in 2017 to $1104.5 million in 2022 (Business Wire 2017).