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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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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.
