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27 Figure 3-2. LGA arrestor: peeling paint. Figure 3-3. MSP Airport: soft tops on EMAS blocks. instrumentation, embedded or otherwise, that could char- higher exit speeds than others. Airports were asked to provide acterize the arrestor bed's internal condition and expected the design aircraft and corresponding exit speed ratings for performance capabilities. each EMAS. For the 11 arrestor systems of the survey, 37 aircraft/ exit-speed combinations were reported. These combinations 3.2. Participating Survey Airports constituted the design cases for the arrestors. The distribution Surveys were sent to 16 airports, and 14 of those airports of design cases over intervals from 0 to 80 knots is shown in Fig- returned completed surveys. The airport names, location IDs, ure 3-6. Of all the design cases, 14% of the aircraft had design aircraft rescue and fire fighting (ARFF) indexes, approximate exit speeds below 40 knots; 62% had design speeds between number of annual operations, and number of EMAS arrestors 40 and 70 knots; and 24% had design exit speeds greater than are shown in Table 3-4. 70 knots. For the cases below 40 knots, it should be noted that the arrestor beds involved still met the 40-knot standard for a number of aircraft, but not all aircraft listed. 3.3. Standard EMAS FAA AC 150/5220-22a defines an EMAS as standard if it has 3.4. FAA Requirements the capacity to arrest an aircraft at 70 knots (1). A non-standard EMAS is compliant if it has the capacity to arrest an aircraft As part of the survey, airport operators were questioned at the minimum exit speed of 40 knots. To assess airport about FAA requirements pertaining to arrestors. When asked conformity with these requirements, airports with an EMAS whether FAA requirements for arrestor bed performance were asked whether each of their arrestors was standard. are too rigid, 8% responded yes, 54% responded no, and 38% Airports that returned surveys had installed 11 arrestors responded no opinion. Similarly, when asked whether FAA altogether. Four of those 11 arrestors were listed as standard, requirements for RSA dimensions are too rigid, 31% responded and 7 of them were listed as non-standard (Figure 3-5). yes, 46% responded no, and 23% responded no opinion. These results are also shown in Figure 3-7. Each EMAS receives an exit speed rating for all the aircraft Airport operators were also asked to provide verbal commen- that it must service. Typically, some aircraft can be arrested at tary on FAA requirements concerning arrestor bed perfor- mance and RSA dimensions. Those comments are summarized Table 3-3. EMAS specifications in the following list: for MSP airport. The 70-knot requirement for the standard arrestor could Parameter EMAS 1 be lower; Runway 12R FAA regulations could consider that, in some cases, an RSA Length 160 ft with an arrestor is safer than an RSA that satisfies general dimensional requirements; and Width 216 ft FAA regulations could consider permitting damage to nose Setback 630 ft gear in extreme overrun scenarios.