Managing ATA Chapters
When you add a system/subsystem for systems and powerplant analysis or L/HIRF analysis, or a structure/substructure for structural analysis, you will be prompted to select from a predefined list. This ensures that the maintenance significant item (MSI) and structural significant item (SSI) numbers used in each analysis comply with the numbering scheme established by the Airlines for America (A4A).
The software provides a predefined list of chapters (aka systems or structures) and sections (aka subsystems or substructures) that are based on the latest iSpec 2200: Aircraft Systems document published by the Airlines for America. In a secure database, only users with the "Manage MPC settings" permission have the ability to modify this list for the current database. Any changes to this master list will apply to all analysis projects in the same database.
To open the Manage ATA Chapters window, choose Home > Hierarchy Defaults > Manage ATA Chapters.
The left panel shows the list systems/structures, while the right panel shows the subsystems or substructures for the one that's currently selected.
Each item is defined by an ATA # and a Description. For chapters, the check marks indicate which type(s) of analyses can be performed. Specifically:
- If a check mark appears in the Systems Analysis column, the item will be included in the list when users build the system hierarchy for aircraft systems and powerplant analysis and the L/HIRF hierarchy for L/HIRF ED/AD analysis in LHSI projects.
- If a check mark appears in the Structural Analysis column, the item will be available when users build the structural hierarchy for aircraft structural analysis.
To edit the properties for an existing item, double-click the row or select the row and click the corresponding Edit button. To add a new item, click the Add button. To delete an existing item, select the row and press Delete or click the Delete button.
What's Changed? In MPC 3, the ATA numbers for subsystems had to be identified in multiples of 10 (i.e., 10, 20, 30, 40, etc.). In the current version, the software allows you to use any number. However, if you add a subsystem/substructure number that is not a multiple of 10, you will not be able to add sub-subsystems or sub-substructures in that branch of the hierarchy. In other words, if you enter 15, the application treats this as a sub-subsystem/sub-substructure, even if it is located in the second level of the tree.
If you click the Set as default for future databases button, the application will save the settings to the MPCDefaults.mpd21 file on your computer (C:\User\USERNAME\My Documents\ReliaSoft\MPC21). Any new databases that you create from this computer will use these saved customized settings by default.
ATA Numbers
The traditional ATA numbering scheme requires that second level numbers be entered in multiples of 10. In addition, the third level numbers are defined within the range specified by its parent (e.g., for the subsystem/substructure with the number 10, the numbers 11 through 19 are valid for the sub-subsystems/sub-substructures).
The ATA Number used in reports consists of at least four numbers, where the first two numbers are determined by the system/structure, the third number is determined by the subsystem/substructure and the fourth number is determined by the sub-subsystem/sub-substructure. For example, ATA # 231500 represents the following configuration:
- System = 23 Communications
- Subsystem = 10 Speech Communications
- Sub-subsystem = 15 SATCOM
You can also use the extended format, where the first two numbers are determined by the system/structure, the third and fourth numbers are determined by the subsystem/substructure and the fifth and sixth numbers are determined by the sub-subsystem/sub-substructure. For the example given above, this would be 231015. Specify which format you want to use in the MPC Application Setup.