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25 CHAPTER 3 Survey of U.S. Airport Operators To obtain information and opinions regarding the existing Site preparation was a significant cost for the airport at EMAS from end-users, a survey was taken of 14 U.S. airports, the time of installation. Since installation, landing light arrays and site visits were made to three. This section summarizes the that come up through the bed are difficult to access due to the findings of the survey data and personnel interviews. As such, obstruction created by the arrestor blocks. the information is a mixture of objective data and subjective Factors that JFK personnel identified for future improve- opinions. The opinions and ideas expressed are those of the ment to the arrestor included better quantification of life-cycle participating individuals and do not reflect the positions or characteristics, such as (1) the effects of rainfall on the arrestor recommendations of the ACRP. bed, (2) the effects of freezethaw cycles on degradation of the arrestor material, and (3) the effects of good or poor mainte- nance on long-term performance. 3.1. Site Visits In July 2007, site visits were made to three airports with EMAS 3.1.2. LGA Airport Site Visit arrestors: John F. Kennedy International (JFK), LaGuardia Airport (LGA), and MinneapolisSt. Paul International (MSP). LGA airport has two EMAS arrestors installed at the facility, At each of these airports, discussions were held with operations, as shown in Table 3-2. maintenance, and management personnel regarding their LGA has a maintenance agreement with the manufacturer, experiences with EMAS. which performs quarterly inspections; on-site maintenance personnel perform daily visual checks of the arrestors. Painting and joint re-caulking have been historical maintenance issues 3.1.1. JFK Airport Site Visit with the bed, and are included in the manufacturer maintenance JFK has two arrestors installed at the facility, as detailed in agreement. The painting and caulking repairs typically must Table 3-1. Runway designations indicate the departure end of be done at night due to the associated runway closure, but night the runway where the EMAS is installed. temperatures and the required cure times can make this dif- Several overrun incidents have occurred at JFK since the ficult. Drainage seems to be an issue; water can be seen to seep installation of the arrestor beds. Airport management per- out of the arrestor for a day after a substantial rain. Figure 3-1 sonnel believe that two or three of these overruns could have and Figure 3-2 show some maintenance issues; repair of such resulted in aircraft damage or occupant injury if the arrestor issues is fairly routine. systems had not been present. Factors that LGA personnel identified for future improve- JFK has a maintenance agreement with the manufacturer, ment to the arrestor included similar life-cycle considerations which performs quarterly inspections; on-site maintenance as for the JFK facility. Additionally, they expressed a desire personnel perform daily visual checks of the arrestors. The beds to see future arrestor construction handled more like other experience some washout of material. Personnel have related paving projects, with standardized ASTM material tests/ that there does not seem to be a good method at present for specifications and multiple vendors that could bid on the work. determining moisture content inside the arrestor beds. Painting They hope to see strides made toward including embedded and re-caulking have been historical maintenance issues with sensors in future arrestors, allowing for ongoing monitoring of the bed and are included in the manufacturer maintenance the internal environment of the arrestor blocks. They would like agreement. metrics for characterizing the aging of an arrestor, allowing

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26 Table 3-1. EMAS specifications for JFK airport. Table 3-2. EMAS specifications for LGA airport. Parameter EMAS 1 EMAS 2 Parameter EMAS 1 EMAS 2 Runway 4R 22L Runway 22 13 Length 392 ft 405 ft Length 275 ft 327 ft Width 200 ft 227 ft Width 170 ft 170 ft Setback 35 ft 35 ft Setback 35 ft 35 ft comparison of current expected performance as a percentage In response to the deterioration issues, MSP engaged in of the original level. small-scale research efforts. The humidity inside the bed was measured and found to be approximately 100% (9). Rough in-situ compression tests were performed on blocks of the 3.1.3. MSP Airport Site Visit bed prior to removal and replacement (10). Though the tests MSP airport has one EMAS arrestor installed at the facility, only produced approximate measurements, they indicated as shown in Table 3-3. It should be noted that this bed was that there was a substantial loss of compressive strength in the installed in 1999, and it featured an older version of the current material. A notable change in compressive strength would have EMAS technology. It was later refurbished, but not replaced, performance implications when compared with the original to provide for improved drainage; maintenance issues for this design specifications of the bed. bed should not be considered typical since the construction MSP used the manufacturer for arrestor maintenance on was atypical. an as-needed basis until 2006, when MSP assumed such tasks. The MSP arrestor has exhibited unusual degradation prob- The manufacturer continues to perform annual inspections lems, with severe "soft tops" occurring on multiple blocks in the and undertakes repairs. bed. The tops appear cup-shaped, and walking on the surface of MSP considered positive aspects of the arrestor design to the bed produces an atypical crunching sound (Figure 3-3). include its passive nature, minimal mechanical complexity, This deformation can be visually observed to increase after and minimal impact on airport operations. a rain or when the temperature rises. The material inside During discussions with MSP personnel regarding future apparently deteriorated, leading to washout of a substantial development, some interesting observations were made. MSP volume (Figure 3-4). Explanations for the basis of the dete- has seen a decrease in mid-size aircraft traffic at the airport, with rioration vary, and include things such as inadequate main- the majority of air traffic falling into smaller (under 99K lb) tenance, poor drainage, or insufficient techniques for the or larger (over 300K lb) size brackets; this could influence the refurbishment process. Airport personnel speculated that design process as it affects the set of design aircraft for a facility. moisture entrapment in the arrestor combined with the severe Secondary arrestors, such as fail-safe net arrestors positioned freezethaw cycles of the Minneapolis climate led to the at the end of the arrestor bed, were considered a favorable degradation. concept. Similar to JFK and LGA, there was a strong desire for Figure 3-1. LGA arrestor (left) out-washing of material and (right) peeling of joint tape.