Open Skies Treaty

Fact Sheet
Office of the Spokesperson
Washington, DC
March 23, 2012

The Department of State welcomes the 20th Anniversary of the signature of the Treaty on Open Skies on March 24, 1992.

Origin and Purpose

The Treaty on Open Skies entered into force on January 1, 2002, and currently has 34 States Parties. The Treaty establishes a regime of unarmed aerial observation flights over the entire territory of its participants. The Treaty is designed to enhance mutual understanding and confidence by giving all participants, regardless of size, a direct role in gathering information about areas of concern to them. Open Skies is one of the most wide-ranging international efforts to date to promote openness and transparency of military forces and activities.

The original concept of mutual aerial observation was proposed by President Eisenhower in 1955 and the Treaty concept was re-introduced as a multilateral initiative of President George H.W. Bush in 1989. The Treaty was negotiated by the then-members of NATO and the Warsaw Pact, and was signed in Helsinki, Finland, on March 24, 1992. The Treaty has been in effect for a decade, following an extended provisional period of application. Since 2002, States Parties have successfully conducted over 840 observation flights over each other’s territory.

Since signature of the Open Skies Treaty in 1992, the security environment in Europe has changed significantly. The Open Skies Treaty continues to contribute to European security by enhancing openness and transparency among the Parties.


The 34 States Parties to the Open Skies Treaty are: Belarus, Belgium, Bosnia-Herzegovina, Bulgaria, Canada, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Poland, Portugal, Romania, Russian Federation, Slovak Republic, Slovenia, Spain, Sweden, Turkey, United Kingdom, Ukraine, and United States. Kyrgyzstan has signed but not yet ratified. The Treaty depositaries are Canada and Hungary.

The Treaty is of unlimited duration and is open to accession by other States. States of the former Soviet Union which have not already become States Parties to the Treaty may accede to it at any time. Applications from other interested States are subject to a consensus decision by the Open Skies Consultative Commission (OSCC), the Vienna-based organization charged with facilitating implementation of the Treaty, to which all States Parties belong. Eight states have acceded to the Treaty since entry into force: Finland, Sweden, Latvia, Bosnia-Herzegovina, Croatia, Slovenia, Estonia, and Lithuania. One application for accession is pending before the OSCC.

Basic Elements of the Treaty

Territory: The Open Skies regime covers the territory over which the State Party exercises sovereignty, including - land, islands, and internal and territorial waters. The Treaty specifies that the entire territory of a State Party is open to observation. Observation flights may only be restricted for reasons of flight safety, not for reasons of national security.

Aircraft: Observation aircraft may be provided by either the observing Party or by the observed Party (the "taxi option"), at the latter's choice. All Open Skies aircraft and sensors must pass specific certification and preflight inspection procedures to ensure that they are compliant with Treaty standards. Certified Open Skies aircraft include:

Bulgaria An-30
Hungary An-26
POD Group C-130 (Benelux, Canada, France, Greece, Italy, Norway, Portugal, Spain)
Romania An-30
Russian Federation An-30 and TU-154
Sweden Saab-340
Turkey Casa CN-235
Ukraine An-30

United States OC-135B

Sensors: Open Skies aircraft may have video, optical panoramic and framing cameras for daylight photography, infrared sensors for a day/night capability, and synthetic aperture radar for a day/night, all weather capability. Photographic image quality will permits recognition of major military equipment (e.g., permit a State Party to distinguish between a tank and a truck), thus allowing significant transparency of military forces and activities. Technology advancements have made film cameras increasingly obsolete and, consequently, the United States is actively preparing for the transition to digital electro-optical sensors. Sensor categories may be added and capabilities improved by agreement among States Parties. All equipment used in Open Skies must be commercially available to all participants in the regime.

Quotas: Each State Party is obligated to receive a certain number of observation flights, i.e., its passive quota. Each State Party may conduct as many observation flights – i.e., its active quota - as its passive quota. The Russian Federation and the United States each have an annual passive quota of 42, while the other States Parties have quotas of 12 or fewer. The Parties negotiate the annual distribution of the active quotas each October for the following calendar year. Around 100 observation flights are conducted each year. Typically, the United States receives 6-8 observation flights from Russia each year, while we conduct 14-16 flights in Russia.

Data Sharing/Availability: Imagery collected from Open Skies missions is available to any State Party upon request, with the cost being covered by the requesting party. As a result, each State Party may obtain more data than it actually collects under the Treaty quota system.

Implementation of the Treaty

In June 2010, the U.S. chaired the Second Review Conference for the Treaty, at which all States Parties confirmed their commitment to full Treaty implementation. The United States considers the Open Skies Treaty to be a key element of our Euro-Atlantic security architecture. The broad cooperation by all Treaty Parties, especially in sharing observation flights, is but one hallmark of the Treaty’s success. Future implementation depends on the sustainability of the aircraft fleet and transition to digital sensors. Enhanced cooperation among States in this area is under consideration in the OSCC.

The OSCC continues to address modalities for conducting observation missions and other implementation issues. The OSCC has monthly plenary meetings during three several-month sessions each year. The OSCC has several informal working groups that take up technical issues related to sensors, notification formats, aircraft certification and rules and procedures. The OSCC main functions are to:

-- consider questions relating to compliance with the Treaty;
-- seek to resolve ambiguities and differences of interpretation that emerge during Treaty implementation;
-- consider and decide on applications for accession to the Treaty;
-- review the distribution of active quotas annually.

The OSCC was established by Article X and Annex L of the Treaty, and has been in session since Treaty signature in March 1992. The OSCC takes decisions by consensus, and has adopted 160 Decisions since its inception. OSCC Decisions enter into force with the Treaty and have the same duration as the Treaty.

For further information on the Open Skies Treaty, visit //

PRN: 2012/450