Free-Flight and en Route Air Safety: A First-Order Analysis

Under present arrangements, U.S. commercial planes do not travel “as the crow flies” from origin to destination; rather, they are generally restricted to paths within a grid. New technologies, however, raise the possibility of moving to a “free-flight” regime under which planes could fly directly from point to point. Striving for general insight rather than definitive conclusions, we use geometrical probability to assess how free-flight could affect the safety and efficiency of en route air traffic operations. We work with two air traffic control sectors: one hypothetical and the other based on actual traffic patterns over Albany, New York. Though tentative, the results suggest that—so long as certain operational constraints are retained—the changed geometry of flight paths after a transition to free-flight might tend in itself to diminish mid-air collision risk. Much depends, however, on whether the human/technological capabilities of future air traffic control can match the extraordinary effectiveness of the existing system.