Negotiations: beginning of February 1990
Signature: 24 March 1992
Ratification: from 17 July 1992
Entry into force: After 20 states have ratified, including the states with passive quotas equal to or greater than eight
Total number of ratifications by end of 1995: 22. Two states with passive quotas greater than 8 (Russia and Ukraine) still have to ratify in order for the Convention to enter into force
Duration: unlimited.
The concept of 'open skies', which was first introduced 40 years ago by President Eisenhower as a measure which might improve confidence between the USA and the Soviet Union, has recently been taken up again in an agreement which commits the states parties to make their territories open to overflying by peaceful flights by other states parties to the treaty.
The Treaty covers the area between Vancouver and Vladivostok, heading in an easterly direction.
The geographical size of each state determines the so-called 'passive quotas', i.e. the number of overflights each state is required to agree to each year. The 'active quotas' represent the number of flights which each state is permitted to make over the other states' territory.
Aircraft may only carry certain specified equipment to observe the ground, and to enable all states to participate on an equal footing from the outset, only the most accessible overflying systems will be used during the first stage covering the first three years.
The Open Skies Treaty marks the beginning of a new stage in the promotion of greater transparency between states. The great powers have satellites capable of carrying out inspections of the whole territory, while the other countries are always left in the dark about the activities of potential enemies. This agreement could go some way towards reducing this asymmetry. It could also prove very useful in verifying the implementation of the provisions of treaties for which no air monitoring is provided in the verification system.