WEATHER INFORMATION SYSTEMS W is a critical factor in aircraft operations. It is the largest single contributor to flight and a major cause of aircraft accidents A study conducted for NASA by Ohio State University reported that the principal diffi- culties in making proper flight decisions are the timeliness and clarity of weather data dissemination. To advance the technology of in-flight weather reporting, Langley Research Center developed in the early 1990 s a cockpit weather information system known as CWIN ( Cockpit Weather Information). The system draws on several commercial data sensors to create radar maps of storms and lightning, together with eports of surface observations. Shown above is a cwin display in the simulation cock pit of Langley's Transport Sys- tems Research Vehicle, a modified jetliner used to test advanced technologies. The CWin display is the lower right screen among the four center panel screens. By push ing a button, the pilot may select from a menu of several displays, such as a ceiling and visibility map, rad ar storn map, or lightning strike map Courtesy of National Aeronau tics and Space Administration. in lengthy procedures for validation and certification. The brickwalling of software modules in a system during the initial development process to ensure isolation between critical and noncritical modules has been helpful in easing the certification process. There are no standard software programs or standard software certification procedures. RTCA has prepared Document Do-178 to provide guidance(as opposed to strict rules) regarding development and certification of avionics civil software. The techniques for developing, categorizing, and documenting avionics civil software in DO-178 are widely used For military avionics software, the principal document is DOD-STD-498. This standard defines a set of activities and documentation suitable for the development of both weapon systems and automated information stems. Many software languages have been used in the past in avionics applications; however, today there is a strong trend for both military and avionics civil software to use Ada wherever reasonably possible The evolving definition of a standards for Applications Exchange(APEX) software promises to provide a common software platform whereby the specialized requirements of varying hardware(processor)requirements are minimized. APEX software is a hardware interface that provides a common link with the functional software within an avionics system. The ultimate benefit is the development of software independent of the hardware platform and the ability to reuse software in systems with advanced hardware while maintaining most, if not all, of the original software design. e 2000 by CRC Press LLC© 2000 by CRC Press LLC in lengthy procedures for validation and certification. The brickwalling of software modules in a system during the initial development process to ensure isolation between critical and noncritical modules has been helpful in easing the certification process. There are no standard software programs or standard software certification procedures. RTCA has prepared Document DO-178 to provide guidance (as opposed to strict rules) regarding development and certification of avionics civil software. The techniques for developing, categorizing, and documenting avionics civil software in DO-178 are widely used. For military avionics software, the principal document is DOD-STD-498. This standard defines a set of activities and documentation suitable for the development of both weapon systems and automated information systems. Many software languages have been used in the past in avionics applications; however, today there is a strong trend for both military and avionics civil software to use Ada wherever reasonably possible. The evolving definition of a standards for Applications Exchange (APEX) software promises to provide a common software platform whereby the specialized requirements of varying hardware (processor) requirements are minimized.APEX software is a hardware interface that provides a common link with the functional software within an avionics system. The ultimate benefit is the development of software independent of the hardware platform and the ability to reuse software in systems with advanced hardware while maintaining most, if not all, of the original software design. WEATHER INFORMATION SYSTEMS eather is a critical factor in aircraft operations. It is the largest single contributor to flight delays and a major cause of aircraft accidents. A study conducted for NASA by Ohio State University reported that the principal diffi- culties in making proper flight decisions are the timeliness and clarity of weather data dissemination. To advance the technology of in-flight weather reporting, Langley Research Center developed in the early 1990’s a cockpit weather information system known as CWIN (Cockpit Weather Information). The system draws on several commercial data sensors to create radar maps of storms and lightning, together with reports of surface observations. Shown above is a CWIN display in the simulation cock￾pit of Langley’s Transport Sys￾tems Research Vehicle, a modified jetliner used to test advanced technologies. The CWIN display is the lower right screen among the four center panel screens. By push￾ing a button, the pilot may select from a menu of several displays, such as a ceiling and visibility map, radar storm map, or lightning strike map. (Courtesy of National Aeronau￾tics and Space Administration.) W