The ACN / PCN method is an international standardized system developed by the International Civil Aviation Organization (ICAO) to provide information on the strength of aeronautical pavements (civil and military aerodromes).aeronautical pavements (civil and military aerodromes), enabling the admissibility of each aircraft to be judged according to its load and the strength of the pavements.The ACN represents the aggressiveness of the aircraft, and the PCN the load-bearing capacity of the pavement structures: an aircraft is admissible without restriction on an aeronautical pavement if ACN PCN; a special study must be carried out to judge the admissibility of the aircraft.