* a) prevent collisions between aircraft in the air;* b) assist in preventing collisions between aircraft moving on the apron or the* maneuvering area, and between aircraft and obstructions on the* maneuvering area;* c) expedite and maintain an orderly flow of air traffic;* d) provides advice and information useful for the safe and efficient conduct of* flights;* e) notify appropriate organizations regarding aircraft in need of search and rescue aid and assist such organizations as required.