On the other hand, since aircraft are also used in international transport the International Civil Aviation Treaty and international standards (ICAO standards), based on the said treaty, stipulate international rules with respect to safety and environmental protection (including noise control standards). These rules set down safety and pollution (such as noise pollution) control standards in addition to specifying basic requirements with respect to inspections.
　The Japanese aircraft inspection system, based on the Civil Aviation law, is described below. It shows due consideration to the above mentioned systems and international rules.

(1) Safety Regulations

1) Airworthiness Certificate

　An aircraft is required to undergo government inspections to check conformity with safety standards, including those for strength, structure and performance, and obtain an airworthiness certificate before it is allowed to fly. Moreover, the validity of airworthiness certificate is one year (in the case of aircraft employed for air transportation services, a period designated by the minister of transport).
　The government conducts two types of inspections, initial inspection for the purpose of issuing an airworthiness certificate and an inspections for extension of the airworthiness certificate upon its expiry.
　Initial inspections include checks on aircraft design, conditions during manufacture and upon completion, among others. But in the case of aircraft carrying type certificate and aircraft imported from countries which are signatories to the International Civil Aviation Treaty and carrying type certificates issued by such countries, design inspection and a part of the inspections during the manufacturing process may be waived.
　During airworthiness certificate renewal inspections the current condition of the aircraft with respect to continuing maintenance of airworthiness is checked.

2) Type Certificate

　With respect to the design of the aircraft, the aircraft shall be issued a type certificate when, as a result of inspections, the type design is found to comply with safety standards with respect to strength, structure and performance.
　This type certificate system has been introduced to facilitate mass production of the same type of aircraft. Since it is issued prior to airworthiness certificate, it is used mainly to waive a part of airworthiness inspections of individual aircraft.
　In case of changes in the design after the type certificate has been issued, if such changes undergo government inspection and are approved, the modified aircraft is considered to be carrying a type certificate and will therefore be qualified for a waiver on a part of airworthiness inspections. However, the said certificate may not be issued to anyone other than the one to whom the original type certificate was issued.

3) Repair and modification inspection and confirmation by certified aircraft mechanic

　When an aircraft undergoes repair (repair or maintenance) or modification, and the said work is likely to have a significant impact on the airworthiness of the aircraft the government shall conduct inspection on the repair and modification work in order to assure compliance with safety standards. In all other cases confirmation by a certified aircraft mechanic shall suffice. An aircraft may not be allowed to fly prior to compliance with this requirement.
　With respect to the capability to repair and modify aircraft, a licensed contractor (a facility licensed to repair and modify aircraft) must carry out repair and modification work, and if upon completion of such work the aircraft is found to conform with safety standards, the requirement for conformation by a certified aircraft mechanic shall be waived.

4) Spare Parts Certificate

　Aircraft parts, such as starters, propellers etc., which have an important bearing on the safety of the aircraft, qualify for being used as aircraft parts only after they have passed inspections for conformation with strength structure and performance standards. Every time such an important part is replaced, the aircraft must undergo government's repair and modification inspection. But if a certified part is employed for the purpose, confirmation by certified aircraft repair mechanic should suffice.
　Spare parts certificates are valid for limited periods and also limit the type of aircraft on which they may be fitted.
　Moreover, with respect to the ability to repair and modify aircraft parts, the law mandates that repair and modification of aircraft parts be carried out at a licensed facility (approved aircraft parts repair and modification facility) and aircraft parts found to conform with safety standards be considered to be the same as those with government's aircraft spare part certificate.

(2) Environmental Regulation

　The law mandates that turbojets may not be put into service unless they undergo government inspection for conformity with noise pollution standards. Moreover, if an aircraft certified for noise pollution standards, undergoes repair or modification likely to affect its noise level, then such an aircraft must undergo government's inspection for aircraft noise related repair and modification. Such an aircraft may not be put into service prior to passing the said inspection.

　Speaking of Japan's aerospace industry, the technological level of Japanese aircraft and aircraft parts manufacturers as well as the quality of their products has improved considerably. This improvement was realized through the manufacture of aircraft at home and participation in international aircraft development projects. Japan's aircraft repair and maintenance contractors have also won acclaim overseas. Evidently they have world class capabilities now.

　The number of aircraft registered in Japan has increased markedly in recent years along with the development of civil aviation in this country. Inspection applications has also grown in tandem and a time has come when inspection often cannot be carried out on the day desired by the aircraft user. Evidently, the current inspection system does not adequately answer users' needs anymore.

　ICAO regulations mandate that an importing country recognize the airworthiness of the aircraft carrying an airworthiness certificate issued in the country of manufacture. In this case the importing country may waive a part or whole of the airworthiness inspection. Internationally, aircraft safety certification is winning greater acceptance and there is growing trend toward waving inspection of individual aircraft on the basis of certification issued by the exporting country.
　Moreover, in recent years aircraft are increasingly being developed jointly by companies in more than one country. This means that designing and manufacturing functions are distributed among several countries. Under the circumstances, in order to prevent duplication of inspection, joint issuance of type certificate is becoming the norm, particularly in US and European countries. Moreover, coordination in the system of licensed aircraft repair and maintenance contractors has also progressed considerably in recent years.

　ICAO noise control standards apply to turbojets, propeller driven aircraft and helicopters, the Noise Standards Conformation Certificate System has been in force in Japan for turbojets. But even today Japan does not have noise standards for propeller driven aircraft and helicopters, partly because of the few number of aircraft of this type in this country.
　Nevertheless, noise control standards for these type of aircraft have become commonplace internationally. Moreover, the number of helicopters has seen a marked increase in Japan in recent years. Under the circumstances there is every likelihood that noise pollution caused by these type of aircraft will become a problem in this country.
　Moreover, ICAO standards define permissible aircraft motor emission levels. While this regulation has not been adopted in Japan as yet, many foreign countries seem to be positively considering this option. Moreover the International Treaty on Maritime law, has come into force in 1993. The law requires signatories to regulate aircraft motor emissions. Japan is also preparing to ratify the said treaty.