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84 main-gear tires was due to the braking plus the arrestor resis- After the monolithic bed was completed, a roll-on or spray- tance. As an approximate solution, this approach worked well on polymer would be applied to the surface to seal the bed. and was appropriate. The hand-laying process would require more time than plac- However, a small side study conducted during the meta- ing larger blocks; however, the final bed would have reduced modeling process indicated that braking applied to the main maintenance needs thereafter due to the lack of joints. gear tires could cause the penetration depth to increase. Since the arrestor metamodel loads assumed a non-braked free- 9.6.2. Cost to Establish System spinning wheel, this depth change would not be captured. For a bottomed tire, little increase is feasible and this effect A preliminary estimate was made for the cost to establish a would likely not occur. For a non-bottomed tire, however, the glass foam arrestor system. It must be noted that the cost esti- tendency to penetrate deeper would lead to higher arrestor mate from this section is only a basic approximation for the drag loads on the tire. Since this effect would only apply to the purposes of comparing the different arrestor alternatives. braked wheels of the main gear, it would benefit the deceler- The cost estimate is based on a mixture of information from ation process while not affecting the nose gear. Stopping dis- the manufacturer, the airport survey, and FAA Order 5200.9. tances could be somewhat reduced by this effect, though it is To develop a more accurate estimate of the costs to install unclear by what amount or in what limited subset of arrestor such a system, it is recommended that a detailed cost quote be design cases. sought from a firm qualified to undertake an installation effort. Where possible, the methodologies used were consistent with the prior survey information collected regarding the existing 9.5.5. Effect of Material Seams EMAS (Section 3.5). As previously discussed, seams in the glass foam material The glass foam arrestor concepts would require site prepa- produced notable pulses in the pendulum test strut loading ration and paving similar to the current EMAS. It was assumed (Section 9.3.4.4). However, the metamodels for the material that the costs for this preparation would be identical to the assume a monolithic arrestor bed without seams. site preparation cost for an EMAS. If seams were present in the material, such as in the design In terms of manufacturing cost, lower density versions of concept featuring separate blocks (Section 9.1.1), they could the material are more expensive than the commercially avail- impart pulsed drag loads to the nose gear. Pulsed loads would able insulating product. To provide a conservative cost estimate, require a reduction in the bed depth to ensure that the peak the upper bound for the possible cost range was assumed. loads did not exceed the limit or ultimate thresholds for the nose The installation cost estimate was separated into specific gear. Consequently, the arrestment distances would increase. materials and general installation labor needs. Because these Since the effect of the material seams in a fielded system has costs were specific to the glass foam arrestor concepts, they do not been established, the caveats of Section 9.3.4.4 apply to not have a direct connection to any prior EMAS data. Discus- these observations. sions with a potential manufacturer produced cost estimates for the foam blocks, adhesive to join the blocks, and a polymer top coating material. The labor costs were estimated based 9.6. Estimated System Cost on similar labor needs for installation of glass foam in roof and Upkeep applications. Finally, the site preparation and estimated EMAS costs were 9.6.1. Installation Process computed in two ways: (1) assuming average survey costs from The arrestor beds would likely use sloped entry and terraced this research, and (2) assuming FAA Order 5200.9 costs. The sides regions, with a slight vertical depression below the runway final cost estimates for both options are given in Table 9-8 level (described further in Section 9.5). For the block variant and Table 9-9, respectively. of the system, the glass foam would be manufactured and Using the survey cost assumptions of Table 9-8, a 300-ft assembled into the larger blocks while at the production arrestor bed would cost approximately 7% less than the cur- facility. These blocks would then be transported to the airport rent EMAS design. If the Order 5200.9 costs are assumed, and laid in place in the RSA. Because of the lower density of the glass foam system would be nominally 37% more expen- the material (6 pcf), a 4-ft block may only weigh 200 lbs; this sive (Table 9-9). Due to the preliminary nature of the esti- could permit placement of the blocks using pallet jacks or mated system cost, it is feasible that actual costs for the system dolly-type devices rather than forklifts. After placement, the would be higher based on unforeseen elements. A conservative seams would be sealed using joint tape or caulk. approach would conclude that the cost for this concept will For the monolithic variant, the glass foam would be shipped probably be similar to that of EMAS. to the site without prior assembly. The small blocks would then In addition to the tables in this section, longer-term life-cycle be hand-laid in rows and layers, with glue applied in between. issues could also be considered. FAA Order 5200.9 includes a