The nation's military-service academies could be stripped of one of their chief tools for bringing in black, Hispanic, and American Indian students as a result of regulatory changes being considered by the Department of Defense, officials of the U.S. Air Force Academy said last week. The proposed change in the department's directives to its service academies would end their ability to favor minority and female applicants in determining admissions to affiliated "academy preparatory schools," which offer an additional year of academic instruction to students viewed as unready to enter the service academies themselves. The Air Force, Army, and Navy service academies continue to give consideration to race and ethnicity in their admissions decisions, and none of the changes being considered by the Pentagon would end that practice. But if the academies are precluded from giving priority to minority and female applicants in deciding which applicants to send to their preparatory schools for training to meet their standards, the result is likely to be a substantial drop in their minority enrollments, said Colonel Carpenter, the Air Force Academy's admissions director.