Appendix 1 - Occupant Trajectory and HIC - FAA

5/19/03 AC 20-146Appendix 1APPENDIX 1OCCUPANT TRAJECTORY AND HICThere has been an extensive amount of research focusing on the analytical prediction ofHIC, head impact velocity, head impact angle, and other analytical data related to fullscaledynamic testing. The information provided in this Appendix will illustrate some ofthe items to consider when conducting a HIC and head path trajectory validation(reference Section 7.1.1.1 and 7.1.1.4). Figures 1 through 4 in this Appendix weregenerated and provided by the National Institute for Aviation Research (NIAR) atWichita State University.Figure 1 shows an XZ-Plane view of a Hybrid II ATD MADYMO model in a preteststate at 1G. In addition to the Hybrid II ATD, the following items are modeled:• Seat back• 2-point restraint• Seat pan• Bulkhead• Foot rest• FloorConsistent with Section 7.1.1.1, occupant trajectory or position is established using theSeat Reference Point (SRP) as the datum. The SRP is identified in Figure 1. In addition,the seat setback, or distance from the SRP to the bulkhead, is also shown. In general, theinformation provided in Figure 1 is considered a minimum for this type of analysis.BulkheadSeat backHybrid II ATD2-point restraintSeat referencepointSeat panSeat setbackFoot restFloorzyxFigure 1 - Pretest Geometry at 1GA1-1

5/19/03 AC 20-146Appendix 1Sled TestAnalysisHIC 694706t (ms)2424Avg. Accl. (g's) 6161Figure 4 – Test and Analytical HIC ValuesA1-5