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44 Figure 6-1. Approval paths for system approval. that the mechanical behavior be sufficiently analogous to 6.4. Updating of the permit the same predictive models to be employed (i.e., the ARRESTOR Code ARRESTOR code, etc.). However, improvements in other areas, such as life-cycle performance, would be encouraged. For the near-term development of alternative materials To demonstrate equivalence, the manufacturer would via the equivalent approval process, it would be necessary to (1) conduct thorough material testing, (2) generate feasibil- have a prediction and planning program. ARRESTOR, though ity calculations, (3) perform small-scale tests, and (4) make the an old code at present, can predict arresting distances for case for equivalence in report form. The FAA would then review various bed geometries. It models a general crushable foam this report and make a determination as to how compelling material and permits the user to specify different compression the data appears. strengths to be modeled. As such, ARRESTOR could serve the Develop Predictive Model Develop Concept · Incorporate testing and modeling FAA Approval data from past · Validate accuracy of model Initial Data Collection & Testing Full Scale Testing Develop Design Program · Mechanical Behavior · Full-scale aircraft testing using · Allows planning for particular · Life-Cycle Expectations transport-category aircraft facility · Requires FAA cooperation Initial Feasibility Calculations · Material energy capacity Apply for FAA Cooperative · Estimated arrest distance Research and Development · Estimated deceleration Agreement Initial Modeling Small Scale Testing · Numerical model (FEA, CFD, · One-wheel bogey tests, or DEM, etc) of one-wheel bogey equivalent if active system · Vary speeds, tire pressure, · Sample bed cross -section aircraft mass, landing gear environmental test configuration Figure 6-2. Proposed normal approval process for new arrestor systems in general.
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45 Develop Material Integrate Into Design Program (ARRESTOR) · Depends upon material and FAA Approval manufacturer · Allows planning for particular facility Submit FAA Equivalence Material Testing Report · Mechanical Properties · Present data · Life-Cycle Properties · Demonstrate EMAS equivalence Initial Feasibility Calculations Small Scale Testing · One-wheel bogey tests · Material energy capacity · Sample bed cross-section · Estimated arrest distance environmental test · Estimated deceleration Figure 6-3. Proposed equivalence approval path for new crushable bed arrestor systems. up-and-coming manufacturers who do not have in-house generalized aircraft model of arbitrary size, combined with predictive codes. parametric variation across a range of values. Other approaches ARRESTOR currently has a limited library of aircraft: the may be possible. B707, 727, and 747. Only one of these aircraft is still in broad Alternately, a new design program could be developed. The service, the B747. To act as a modern planning tool, a broader Arrestor Prediction Code (APC) developed in the current effort range of aircraft is needed. It is possible to accomplish this (Appendix G) could serve as the basis for such a replacement. through two means. First, the aircraft manufacturers could be For new manufacturers to participate actively in the arrestor solicited for actual aircraft data. Second, the code could use a system market, an updated predictive code would be necessary.