On December 7th 1944, 52 countries have endorsed the Chicago convention, and agreed to set up and applied a technical regulation based on the ICAO (International Civil Aviation Organisation) directives. The Chicago convention applied since April 4th 1947. All the organisations implied in the aviation safety are concerned: airlines, maintenance workshop, training school, crews …
Charter and regular airlines are controlled by the Civil Aviation Authority of the state where they have set their main base. Therefore, the National Authority of an airline is responsible for ensuring that its air carrier operators comply with the minimum safety oversight standards established by the ICAO. Only the National Authority of the airline has a global knowledge of the safety level of its airline, and can decide whether or not the airline is allowed to carry passengers. Then, it is the responsibility each country to ensure that every foreign airlines have been allowed to fly by their National Authority.
In addition to the complete and systematic controls under the responsibility of the National Authority of the airline, the European states have set up a program called SAFA (Safety Assessment of Foreign Aircraft), which consists in performing punctual and unexpected controls. These controls do not replace the National Authority continuing oversight and surveillance, but ensure that the airlines comply with the international safety requirements. For example, aircraft documentation, crew licenses, flight deck and cabin safety systems, general aircraft aspect, cargo loading are verified. These controls are made in such a way that the aircraft is not delayed. Consequently, depending on the timeframe available during the aircraft stop, these controls can be extensive enough to definitely ensure that the aircraft is safe, or too short and allow an unsafe airline to be undetected.
Following a control, the airline can be requested to correct a deviation before the next take-off. Its National Authority can be warned. In the worst case, in case of a serious deviation, an airline can be banned from a country until it has demonstrated compliance with the international safety standards. The purpose of these controls is to set an additional surveillance of the foreign airlines, and that all foreign airlines know that they can be controlled and sanctioned anythime when they land in Europe. All these controls are carried out by dedicated teams.