Active Quota. The number of observation flights that each State Party has the right to conduct as an observing Party. A Party's active quota may not exceed its passive quota. The initial distribution of such numbers is contained in Section II of Annex A of the Treaty and is subject to annual review in the Open Skies Consultative Commission (OSCC).
Alternate Airfield. An airfield to which an observation aircraft or transport aircraft may proceed when it becomes inadvisable to land at the airfield of intended landing. This category includes emergency airfields and airfields that may be used as a weather alternates if weather at the planned destination is unsuitable for landing.
Danger Area. An airspace of defined dimensions, within which activities dangerous to the flight of aircraft may exist at specified times. This is one of the three types of areas that are covered under the term "hazardous airspace," on the basis of the International Civil Aviation Organization (ICAO) Convention.
Escort. An individual from any State Party who accompanies the inspectors of another State Party.
Flight Crew. Individuals who perform duties associated with the operation or servicing of an observation aircraft or transport aircraft, including interpreters.
Flight Monitor. An individual who, on behalf of the observed Party, is on board an observation aircraft provided by the observing Party during the observation flight.
Flight Plan. A document elaborated on the basis of the mission plan agreed between the observing and observed Parties that is presented to air traffic control authorities. It must be in the format and contain the content specified by the ICAO.
Flight Representative. An individual who, on behalf of the observing Party, is on board an observation aircraft provided by the observed Party during an observation flight. The procedures for designating such individuals, as well as their privileges and immunities, are contained in Article XIII of the Treaty.
Ground Resolution. The minimum distance on the ground between two closely located objects at which they are distinguishable as separate objects. The methodologies for determining the capability of individual sensors to achieve a specified ground resolution, including the minimum altitude from which such a resolution can be achieved, were developed by the OSCC during the Treaty's period of provisional application.
Group of States Parties. Two or more States Parties that have agreed to form a group for purposes of the Treaty.
Hazardous Airspace. The prohibited areas, restricted areas and danger areas, defined on the basis of Annex 2 to the Convention on International Civil Aviation, that are established in accordance with Annex 15 to that Convention in the interests of flight safety, public safety and environmental protection and about which information is provided in accordance with ICAO provisions.
Infra-Red Line-Scanning Device. A sensor capable of receiving and visualizing thermal radiation emitted in the invisible infra-red part of the electro-magnetic spectrum by objects due to their temperatures and in the absence of artificial illumination. Line-scanning devices were selected instead of other types of infra-red sensors to avoid technology transfer problems that might arise with more sophisticated systems.
Individual Active Quota. The number of observation flights that a State Party has the right to conduct each year over the territory of another State Party. These numbers are subject to annual review.
Inspector. An individual from any State Party who conducts an inspection of sensors or observation aircraft of another State Party.
Maximum Flight Distance. The maximum distance over the territory of the observed Party from the point at which the observation flight may commence to the point at which that flight may terminate. The maximum flight distance includes those route segments for intermediate stops, including refueling airfields.
Mission Plan. A document that is presented by the observing Party to the observed Party and forms the basis for the elaboration of the flight plan. The mission plan contains the route, profile (altitudes), order of execution and support required to conduct the observation flight.
Mission Report. A document describing an observation flight, which is completed after the termination of the observation flight by the observing Party and which is signed by both the observing and observed Parties.
Observation Aircraft. An unarmed, fixed wing aircraft designated and certified to make observation flights, registered by the relevant authorities of a State Party and equipped with agreed sensors.
Observation Flight. The flight of the observation aircraft conducted by an observing Party over the territory of an observed Party from the point of entry or Open Skies airfield to the point of exit or Open Skies airfield, as the flight of that aircraft is provided in the flight plan.
Observation Period. A period of time during an observation flight, specified by the observing Party, when a particular sensor installed on the observation aircraft is operating. There is no limit on the number or duration of such observation periods during an observation flight. Sensors may be operated for the entire duration of a flight, so long as the observation aircraft does not deviate from the agreed flight path and the flight altitude is appropriate for each sensor. Information on such sensor operating periods is required because the film or other recording medium has to be annotated with such information. Such information permits all Parties to know when and where data was collected, and permits third Parties to request data taken during specified periods.
Observed Party. The State Party or group of States Parties over whose territory an observation flight is conducted or over whose territory an observation flight is intended to be conducted.
Observing Party. The State Party or group of States Parties that intends to conduct an observation flight, or conducts an observation flight, over the territory of another State Party or group of States Parties.
Open Skies Airfield. An airfield designated by the observed Party as a point where an observation flight may commence or terminate. An Open Skies airfield may be a point of entry or a point of exit, or it may be a separate airfield designated solely as an Open Skies airfield.
Open Skies Consultative Commission (OSCC). The body established to facilitate the provisional application and the implementation of the Open Skies regime and for handling any compliance issues that may arise.
Passive Quota. The number of observation flights that each State Party is obligated to accept as an observed Party. This number, unlike the distribution of active quotas, is not subject to annual review by the OSCC.
Pilot in Command. The pilot on board the observation aircraft who is responsible for the operation and safety of the observation aircraft and the execution of the flight plan.
Point of Entry. A point designated by the observed Party for the arrival of personnel of the observing Party on the territory of the observed Party. The observation flight may also commence at this point if it is also designated an Open Skies airfield.
Point of Exit. A point designated by the observed Party for the departure of personnel of the observing Party from the territory of the observed Party. The observation flight may also terminate at this point if it is designated an Open Skies airfield.
Prohibited Area. An airspace of defined dimensions, above the territory of a State Party, within which the flight of aircraft is prohibited, in accordance with specified conditions. This is one of the three types of areas that are covered under the term "hazardous airspace," on the basis of the ICAO Convention.
Refueling Airfield. An airfield designated by the observed Party to be used for fueling and servicing of observation aircraft and transport aircraft.
Representative. An individual who has been designated by the observing Party and who performs activities on behalf of the observing Party during an observation flight on an observation aircraft designated by a State Party other than the observing Party or the observed Party.
Restricted Area. An airspace of defined dimensions, above the territory of a State Party, within which the flight of aircraft is restricted in accordance with specified conditions. This is one of the three types of areas that are covered under the term "hazardous airspace," on the basis of the ICAO Convention.
Sensor. Equipment of a category specified in Article IV of the Treaty that is installed on an observation aircraft for use during the conduct of observation flights. The categories of equipment specified in Article IV are: optical and framing cameras; video cameras with real-time display; infra-red line-scanning devices; and sideways-looking synthetic aperture radar.
Sensor operator. An individual from any State Party who performs duties associated with the functioning, operation and maintenance of the sensors on an observation aircraft. Such personnel could also be considered to be representatives, flight representatives or flight crew, depending on their duties.
Synthetic Aperture Radar (SAR). Observation aircraft may be equipped with sideways looking synthetic aperture radar. SAR is a high resolution ground mapping technique which takes advantage of the forward motion of a vehicle that is carrying a pulsed radar to synthesize the effect of a large antenna aperture. In other words, the larger the radar antenna (aperture), the higher the radar picture's resolution. SAR uses a radar with a very small antenna (such as can be carried in an aircraft) that synthesizes a series of recurring radar pulse returns to simulate the effect of a much larger antenna aperture; thus, the name "synthetic" aperture. SAR is effective in detecting large objects day or night, even through cloud cover.
Taxi Option. A treaty provision that gives the observed Party the right to demand that its observation aircraft, along with its flight crew and sensors, be used to carry out an observation flight over its territory requested by an observing Party.
Territory. The land, including islands, and internal and territorial waters, over which a State Party exercises sovereignty.
Total Passive Quota. The total number of observation flights that a State Party is obliged to accept over its territory. Passive quotas are allocated by Annex A, Section II of the Treaty.
Transit Flight. The flight of an observation aircraft or transport aircraft over the territory of a third State Party en route to or from the territory of the observed Party.
Transport Aircraft. An aircraft other than an observation aircraft that conducts flights to or from the territory of the observed Party exclusively for the purposes of the Treaty.