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Key facts about Open Skies Treaty

The Treaty empowers its participants to conduct observation flights over the territory of each other to monitor military activity

MOSCOW, January 1. /TASS/. Mutual claims by Russia and the United States on fulfilling the Open Skies Treaty intensified in late December 2017. Starting from January 1, 2018, both countries are planning to alter some bilateral agreements concerning observation flights stipulated in this document.

TASS has prepared a material on this international treaty.

History of signing the Treaty

The Treaty on Open Skies is an international document that established the regime of observation flights over the territory of its participants to exercise control over the implementation of disarmament agreements.

The ‘open skies’ idea was first put forward by US President Dwight Eisenhower at a conference of the heads of four world powers (the USSR, the United States, the UK and France) in Geneva on July 21, 1955. The ‘open skies’ regime, which envisaged an exchange of military information between the USSR and the USA with its verification through mutual aerial surveying of the territories of both countries, was proposed as an element of the comprehensive system of military activity’s control.

The negotiations started in the late 1950s but were halted after an incident with the US reconnaissance plane U-2 in May 1960 (it was shot down in the Soviet airspace).

In the spring of 1989, US President George H.W. Bush proposed to the leaders of the NATO and Warsaw Treaty Organization member states to restart discussing this issue. The first two rounds of the talks were held in 1990 in Ottawa (Canada) and Budapest (Hungary). After that, the negotiating process was continued in Vienna in 1991 and 1992.

The document was initialed in Vienna on March 21, 1992. On March 24, 1992, it was signed in Helsinki by representatives of 27 member states of the Conference on Security and Cooperation in Europe (the Organization for Security and Cooperation in Europe, the OSCE, since 1995). The treaty entered force on January 1, 2002 after it was ratified by 20 countries (Russia ratified the document on May 26, 2001).


Today, 34 OSCE member-states are parties to the Treaty: Belarus, Belgium, Bulgaria, Bosnia and Herzegovina, Great Britain, Hungary, Germany, Greece, Georgia, Denmark, Iceland, Spain, Italy, Canada, Latvia, Lithuania, Luxembourg, the Netherlands, Norway, Poland, Portugal, Russia, Romania, Slovakia, Slovenia, the United States, Turkey, Ukraine, France, Finland, Croatia, the Czech Republic, Sweden and Estonia. Kyrgyzstan signed the Treaty but did not ratify it.

Basic provisions

The Treaty empowers its participants to conduct observation flights over the territory of each other to monitor military activity in compliance with the quotas of surveillance missions stipulated in it. It regulates the conduct of flights, sets requirements for aircraft and observation equipment and establishes the procedure of processing gathered data. This information is included in the database available for all participants.

The flight path of an observation aircraft should not be closer than ten kilometers from the border with an adjacent country that is not a party to the Treaty.

The Treaty allows creating groups. Thus, Russia and Belarus comprise one group of member states and another group is formed by Belgium, the Netherlands and Luxembourg.


The Treaty assigns a certain number of quotas to each member state (including active quotas when a state conducts inspection flights over the territory of another state and passive quotas when it receives the inspections of other states). The United States and the Russia-Belarus group have 42 flights a year each. Germany, Canada, France, Great Britain, Italy, Turkey and Ukraine have 12 flights each. Portugal has the smallest quota (2 flights a year). The member states cannot use the quota wholly for flights over the territory of one state only. Thus, Russia and Belarus may not conduct more than four flights (the quota for the group) over the United States and two flights over Turkey while the United States may not conduct more than eight flights over Russia and Belarus.

Aircraft and aerodromes

Russia uses specially equipped Tu-214ON, An-30 and Tu-154M-Lk-1 planes for observation flights while the Unites States employs Boeing OC135B Open Skies aircraft. The treaty stipulates an option to use the aircraft of an inspected country for observation flights.

Representatives of the country over whose territory a flight is conducted are always present aboard a surveillance aircraft. Flights are conducted from a certain aerodrome. In Russia, such aerodromes are located in Kubinka (the Moscow Region), Ulan-Ude, Magadan and Vorkuta.

Bans on flights

The Treaty does not stipulate any restrictions on observation flights for the considerations of secrecy, national security and so on. However, Article VIII of the Treaty stipulates that the observed Party may prohibit an observation flight, if it violates the procedures stipulated in the document, the requirements for the aircraft’s equipment or the route. No sanctions are envisaged against the observed Party for prohibiting observation flights.


From March 24, 1992 to December 31, 2001, the regime of the Treaty’s temporary application was in effect. Today, about 100 inspection flights are conducted over the territories of its participants annually. The 1,000th flight under the Open Skies Treaty was conducted in the spring of 2012.

In 2011, Georgia unilaterally announced it was terminating cooperation with Russia under the Open Skies Treaty over the conflict around the political status of Abkhazia and South Ossetia (according to the data available as of December 2017, Georgia continues denying Russia the possibility of observation flights).

Mutual claims by United States and Russia

In 2017, Russia and the United States exchanged mutual claims on the fulfillment of the Treaty on Open Skies.

Washington accused Moscow of violating some provisions of the document. In particular, one of its claims related to Russia’s decision in 2014 to set a 500km restriction on the range of flights over the Kaliningrad Region. As the Russian government explained, intensive flights over the limited territory of the Kaliningrad Region (208 km from the east to the west) hindered the normal operation of civil aviation. Besides, the United States also accuses Russia of denying permission to make monitoring flights within the 10km zone along the borders with Abkhazia and South Ossetia. However, Russia, which has recognized the sovereignty of both republics, says that the observance of the buffer zone is guaranteed by the Treaty’s provisions. Washington also accuses Moscow of restricting flights due to the closure of the airspace for air travels by the country’s top officials.

Meanwhile, Russia considers some US acts as deliberately hindering the implementation of the Treaty’s provisions. Specifically, Moscow accuses Washington of delays in agreeing flights over the US territory in the Pacific Ocean.

In September 2017, the United States announced the intention to introduce additional restrictions for Russian planes’ observation flights. However, the US administration did not specify these restrictions. According to The Wall Street Journal, the United States intends to announce a maximum range of no more than 900 km for flights over the Hawaiian Islands. Also, Russian surveillance planes may lose the right to use the US Robins Air Force base in the state of Georgia and the Ellsworth Air Force base in South Dakota, which were earlier used for the crews’ rest and for refueling.

 In response to “unilateral steps related to creating maximum inconveniences for the Russian Open Skies missions,” Russia’s Foreign Ministry announced cancelling night stopovers for US crews at three Russian aerodromes.