Downloaded from https://www.everyspec.com MIL-STD-1808B 4 GENERAL REQUIREMENTS 4.1 System subsystem sub-subsystem number (SSSN). The SSSN referencing shall be used to locate needed data for the technical information required by those documents listed in section 2 . Broad rules for applying the SSSN are outlined in herein. The SSSN numbering system is a dash number breakdown that provides a means for dividing information into system, subsystem, and sub-subsystem. The following instructions provide general procedures for constructing the SSSN using the numbers assigned herein.
The SSSN shall be used in conjunction with the functional requirements of MIL-PRF-9854, MIL-PRF-38807, MIL-PRF-83495, electronic data task oriented view packages developed according to MIL-PRF-87268, and MIL-HDBK-863. 4.1.1 Number composition. The basic SSSN is composed of two- and three-digit elements (see table in step 4.1.1.3 ). The first element (system) and the first digit of the second element (subsystem) are assigned as specified herein (see section 5 ). The second digit of the second element (sub-subsystem) and the third element (subject) are assigned by the manufacturer according to the complexity of the equipment and the numbering application.
The fourth element (function) is used when typical maintenance functions are required. Depending on program needs, such as supportability analysis, configuration management, work unit codes, engineering data, etc., additional elements may be added to the right. 4.1.1.1 System number. When assigning system or subsystem numbers to information applicable to a whole system or whole subsystem zeros shall occupy the applicable elements and digits of the SSSN. For example, Information about the complete Navigation system located in an On-equipment Maintenance Manual Set (OMMS), General System (GS) manual would be assigned the SSSN 34-00-00.
Information contained in this manual must be applicable to the entire Navigation system. 4.1.1.2 Subsystem number. Continuing the example in 4.1.1.1 , if subsystems are so complex that the information cannot be practically covered, additional subsystem breakouts may be required. The information in these manuals would be confined to the specific subsystem, e.g., information for the Dependent Position Determining subsystem would be assigned 34-50-00. 4.1.1.3 Sub-subsystem number. Systems designed with very complex subsystems may require further breakout into sub-subsystems. The sub-subsystem element numbers and descriptions are defined by the manufacturer.
Sub-subsystems shall be indicated by a number greater than zero in the second element, second digit, e.g., 34-51-00. In this case, -51 represents a sub-subsystem, e.g., Global Positioning System (GPS), of the Dependent Position Determining subsystem (34-50-00) of the Navigation System (34-00-00). 2