SBAS FAS Data Block Compare

SBAS FAS Data Block Compare

SBAS FAS (Final Approach Segment) Data Blocks are used in aviation industry to define final approach path parameters for instrument approach procedure. Normally civil aviation authorities create, validate and publish FAS Parameters in national AIP (Aeronautical Information Publication). FAS Data Block is created from those parameters and added with CRC (Cyclic Redundancy Check) value, which provides a level of assurance against loss or alteration of data. Aviation data houses process published data and deliver them to avionic data packers to be included in the aircraft navigation database.

FAS Data Block Compare program is used to compare two data blocks and show differences between them. Usually this is needed after a change in one or more FAS parameters. User can verify that required change is applied correctly by comparing existing block to a new one. Changed parameter(s) are shown using red text. Program inputs are two FAS Data Blocks, existing and a new one. Eurocontrol has online SBAS FAS Data Block Tool, which can be encode FAS parameters to FAS Data Block. This tool can also decode Data Block back to FAS parameters. FAS Data Block contains 72 hex characters (not including spaces) plus 8 characters for CRC, totally 80 characters. Some countries publish data block together with FAS parameters, but some publish only parameters and CRC remainder.

One example of data block (fictional), created using Eurocontrol tool:
10181806050C00000132310538AD181B2C59E4098216B057FD405100F4015E016400C8FA4D87B43E
 
In our change example runway threshold has been relocated 100 m and height raised 1 m. Eurocontrol tool is used to create a new data block.
10181806050C0000013231050694181B2F5CE4098C16E270FD3D4E00F4015E016400C8FA46DA408B

Both data blocks are inserted to program and Decode buttons pressed. Program shows now data blocks with spaces and changes are highlighted by red color. It’s much easier to compare blocks like this than comparing hex blocks.
  • Results, when generated data blocks are inserted, decoded and compared
  • Results saved to pdf-file.

Requirements

  • Operating system Windows 2000 / XP/ 2003 / Vista / 7 / 8 / 10 / 11
  • SBAS Providers supported EGNOS, GAGAN, MSAS and WAAS
  • The Product is provided 'as-is', without any express or implied warranty. In no event shall MR Soft be held liable for any damages arising from the installation or use of this software.

Who needs this

  • Not many, but most likely Flight Procedure Design Service (FPD) providers, who are maintaining and delivering SBAS FAS Data Block parameters for aviation community.

Setup

  • FAS DB Compare Setup.exe (1 098 kt)
  • Setup and program itself have Digital Signature
  • Setup possible without admin rights if not installed to Program Files directory

Documents

  • More details about the FAS Data Block can be found from the following publications (not available as free)
    • RTCA DO-229D
    • ICAO Annex 10
    • ICAO Doc 8168 (PANS OPS) Volume 2

Version history

  • Version 1.0.0.0  21 Feb 2025
    • Public release