Al COMELDEA-EHE as for populations exposed above ground. None of the mortality curves presented here in- clude the probabilities of death from indirect ionizing radiation (fallout). The mortality rates associated with various patterns of fallout are discussed in the Section “‘ Effectiveness of Civil Defense Actions.”’ ACCURACY Delivery accuracy of the enemy attack is of extreme importance to civil defense. planning, especially if movement of the population away from some assumed aiming pointis one of the passive maneuvers under consideration. Since this is one of the most debatable aspects of the attack, this study uses a range of circular probable errors (cep) from 4000 to 12,000 m (cep of 0 were also computed for comparison, purposes but are not cited in this appendix since they do not differ appreciably in their effects from cep of 4000 m). The random fall of the weapon and inaccuracies of the bombsighting mechanisms are probably minor, although these are the bases for the usual computations of cep. Other factors, largely unexplored, may contribute to crp of many miles as opposed to the few hundred feet that practiced crews over friendly territory can sometimes achieve. Some of these factors may be as follows. Effect of Defender Action. Loca] point defenses may destroy the aircraft but not the bomb. This might result in a ground burst many miles from the desired ground zero (pa@z).* Failure To Identify Aiming Point. Although it is presumed that enemy crews will be well briefed on their mission, it is also true that they have not had the advantage of seeing the actual target on radarscopes until the time of the attack. At least one study® indicates that it may be important to distinguish between aiming-point misidentification and being “lost.” The latter behavior is typified by incomplete orientation in which the operator apparently feels compelled to find some point that at least resembles the desired aiming point. As the pattern deteriorates, the operator chooses another point further ahead. In one case cited, a ‘‘lost’’ operator made fourdifferent selections of target area in the course of one bomb run. Intelligence Errors. An Fcpa report states that: ‘‘By analysis of population and in- dustrial concentrations within any target area, we are able to assume what we believe to be a logical aiming point for enemy attack. However, we do not know how complete the enemy’s information may be or whether his attack assumptions are the sameas ours.” ® This is but a partiallist of the factors that may contribute to very large aimingerrors. An oro’ study concerned with predicting safe distances of friendly troops from pez suggests the term “tactical cep (TcEP)’’ to describe more realistically the dispersion of aimed weapons around a point. This paper does not propose to answer the question of how accurately high-altitude bombers can deliver thermonuclear weapons on defended targets. It is suggested, however, that the TcEP, as opposed to the cep attained by friendly crews on practice runs, may be very large.t WARNING TIME The amount of warning time of enemy attack places severe restrictions on possible civil defense maneuvers. Table 4 summarizes the warning times that the six targets under *Appendix H of this report discusses the possibility of destroying the bomb as well as the carrier. Should this tactic be adopted, this factor would not contribute to cEr. tAn Air Force press release of 15 June 1956 indicates that a bomber in the Pacific Proving Grounds Tests missed the paz by “less than four miles.” ORO-R-17 (App B) 19 ee Many factors enter into the accuracy with which a high-altitude bomber can attack some point in a metropolitan complex.