For commercial and large military aviation, crashes are assumed to
occur at random throughout the CONUS, and the variation in traffic
volume is reflected by the variation in the number of aircraft handled in
each ARTCC. For small military aviation, the number of crashes varies
among the ARTCCs. Thus, the expected number of crashes per year is
estimated for each ARTCC based on the distribution of crash locations
in the historical record.
Table B-15 in Appendix B provides reasonable estimates of NPf(x,y) for
selected DOE sites, as well as estimates of a minimum, average, and
maximum value applicable for facilities at other locations within the
It is important to recognize that the in-flight analysis for military aviation
given below only applies to normal in-flight operations outside military
operations areas and low level flight ranges. For facilities at or near
these latter types of areas, it is necessary to perform a site-specific
assessment of the impact frequencies associated with activities in these
The analyses for each of the commercial and military subcategories are
1. Commercial Aviation Air Carrier.
Step 9. Refer to Appendix B, Table B-15, and obtain the appropriate site-specific or
generic value of NPf(x,y).
Step 10. Multiply the value of NPf(x,y) by the A value determined for air carriers in