Scientific Production Organisation [Russian] A type of Russian organisation which can be roughly translated as 'Corp.' or 'Ltd.' For example, NPO Energiya, the Soviet agency in charge of piloted civil space missions. Screen Information displayed on a computer screen at any one time, which might include animation or extra information which may be displayed upon selection. One or more screen(s) grouped together comprise a module. Screens deal with items. Screening When the shape of the terrain or certain objects prevents the detection of targets in certain parts of the airspace, one speaks about screening of the parts of the airspace concerned. Screening Angle Analysis Digitised Terrain A SASS-C tool which calculates the theoretical electro.magnetic visibility for a given radar site from digitised terrain elevation data. The result of calculation is expressed as a series of screening points for each azimuth range. Screening Point A point used in the definition of theoretical electro-magnetic visibility. It is defined by two values: a) by the angle starting from the centre of the earth between the antenna and the point; b) by the altitude of the surface of the earth. Script A cognitive representation that describes the regular sequence of events in specific situations or contexts (e.g. Script of "visiting a restaurant": go inside, wait to be seated, sit down, read the menu, order, etc.). A script may include roles and ramifications for special subscripts. Scripts are stored in the long-term memory. The knowledge that is stored in a script is used for the orientation in situations which occur often. Search and Rescue Region An area of defined dimensions within which search and rescue service is provided. Secondary Plot The radar signal is not bounced back but is received by a transponder in the aircraft which transmits a coded reply giving altitude and identity information. Secondary Radar A radar system wherein a radio signal transmitted from the radar station initiates the transmission of a radio signal from another station. Secondary Surveillance Radar In contrast to normal radars, SSR requires the aircraft to send back (using a transponder) a signal to the radar and thus actively participate in the detection process. Secondary Surveillance Radar (Mode S) In addition to its use for surveillance, the Mode S option of SSR also makes available an air-ground data link which could be used for ATS purposes in the high density airspace. Secondary Surveillance Radar Improvements And Coll The fifth meeting of SICASP (November 1993) recommended the adoption of SARPs and guidance material for both Mode S and ACAS II (Airborne Collision Avoidance System). The third edition of the Manual of the Aeronautical Telecommunications Network was recommended for ICAO publication. Further work on ATN SARPs will be carried over to the ATNP with the manual as a basis. SICASP will continue to work on Mode S data link and ACAS. Secondary Surveillance Radar Response The visual indication, in non-symbolic form, on a radar display, of a response from an SSR transponder in reply to an interrogation.