Abstract: An acoustic collision detection system that enables an aircraft to detect an approaching target, recognize the potential for collision and change course to maintain a safe separation distance, with or without operator invention. The acoustic collision detection system consists of an array of acoustic probes and a digital signal processor which receives acoustic data from the approaching target. The digital signal processor is configured to receive acoustic data from the array of acoustic probes; filter out noise and its own acoustic signals; extract the acoustic signals emanating from the approaching target; calculate the intensity, the bearing and the bearing angle rate of change of the approaching target, and determine whether the aircraft and the approaching target are on a potential collision course.