; 49 U.S.C. 40101 note), within a runway exclusion zone shall be considered a violation of subsection (a) unless— (A) the operator of the unmanned aircraft received prior authorization for the operation from the air traffic control tower at the airport; or (B) the operation is the result of a circumstance, such as a malfunction, that could not have been reasonably foreseen or prevented by the operator. (2) Runway exclusion zone defined In this subsection, the term runway exclusion zone means a rectangular area— (A) centered on the centerline of a runway of an airport; and (B) the length of which extends parallel to the runway’s centerline to points that are 1 statute mile from each end of the runway and the width of which is ½ statute mile. . (b) Clerical amendment The table of sections for chapter 2 of title 18, United States Code, is amended by inserting after the item relating to section 39A the following: 39B. Unsafe operation of unmanned aircraft. .