Airworthiness certification refers to repeatedly testing, verifying, and certifying the flight safety of aircraft in the process of designing, manufacturing, and operating aircraft manufactured, modified, and improved by government representative organizations. In the case of civil aircraft, the International Civil Aviation Organization (ICAO) recommends that the ｢Aviation Safety Act｣ stipulate the relevant grounds, and the Airworthiness Authority (Aviation Policy Office) and the Korea Institute of Aviation Safety Technology (KIAST) provide relevant airworthiness certification. In addition, in the case of military aircraft, the Ministry of National Defense Acquisition Program Administration (Defense Promotion Agency Certification Planning Division), supervising institutions (air force, army), specialized institutions (air force, army, navy, Agency for Defense Development, Defense Agency for Technology and Quality) airworthiness certification and airworthiness maintenance of military aircraft doing the job However, in the case of aircraft of state agencies (police and customs), they are classified as military aircraft according to the ｢Miltary Aircraft Airworthiness Certification Act｣, but there is no authority for airworthiness certification or a specialized agency in charge of remodeling and improvement, and there is no authority for airworthiness certification, so the defense business It is being certified by the certification planning department of the government office. In this regard, we would like to present the direction of operation of airworthiness certification agencies for the modification and improvement of rotary wing aircraft by national agencies (police, customs office).