Aircraft maintenance uses codes for processing information. Some information, such as the aircraft bureau number, is normally expressed in numerical terms; thus, it does not need to be converted into codes. In other cases. the information must be converted into code so it can be machine processed. Basic codes used on the VIDS/MAF are prescribed for Navy-wide use. Therefore, they cannot be changed at local option. Some of the codes are built to provide some flexibility to allow expansion to meet local needs. Some of the principal codes used by aircraft maintenance activities are described below. NOTE: A complete list of the codes can be found in an appendix to OPNAVINST 4790.2. Organization code. The organization code is a three-character. alphanumeric code that identifies an activity within a major command. Permanent Unit Code (PUC). The PUC is a six-character, numeric code assigned to each aircraft reporting custodian for identification. Work Center Code (WCC). The WCC is a three-character, numeric code that is used to identify work centers within an organization. Type Equipment code (TEC). The TEC is a four-character. alphabetic code that identifies the end item of equipment on which work is performed, such as aircraft, engine, or SE. Julian date. The Julian date is a four-character, numeric code used to show the date. The first character of the code is the last digit of the year, and the last three characters of the code show the day of the year. For example. Julian date 6324 is the 324th day of 1996, or November 19, 1996. When used on the VIDSMAF as part of the JCN, the first position (showing the year) is omitted. All dates used on source documents are shown in Julian dates. Job control number (JCN). The JCN is a 9-, 10-. or 11 -character. alphanumeric code used to separately identify each maintenance action. The JCN is made up of four parts: the Organization code. the three-character part of the Julian date that shows the day of the year, a sequence number, and a JCN suffix. The sequence number is either a three-character number that runs sequentially from 001 to 999 or a three-character, alphanumeric number with an alphabetic first character and the last two numbers running sequentially. from 00 to 99. Three-character. sequence numbers are used to identify routine day-to-day maintenance actions, such as AC4-324-216. Three-character, alphanumeric sequence numbers are used only to document major inspections other than preflight, postflight, turnaround, daily, special, conditional, corrosion, and acceptance/transfer inspections. An example of this type of JCN is AC4-324-A00. The JCN suffix is an alphanumeric code that is used by IMAs. It identifies a subassembly, or subassembly repair action completed separately from the major component repair action. This suffix is added to the basic JCN to create the fourth part. Work Unit Code (WUC). The WUC is a one-. three-, five-,   or seven-character numeric or alphanumeric code. This code normally identifies the system, subsystem, set, component. and part of the end item being worked on. The first two characters identify the system and are standardized. Action Taken code. The Action Taken code is a one-character, alphabetic or numeric code that describes what maintenance was performed on an item identified by a Work Unit Code. Commercial and Government Entity (CAGE). This is a five-position code assigned to manufacturer’s and nonmanufacturer’s organizational entities and contractors of items procured by agencies of the Federal Government. This code is commonly called the Manufacturer‘s code. Malfunction Description code. The Malfunction Description code is a three-character, alphanumeric code used to describe the malfunction occurring on or in an end item. These codes are listed in both alphabetical and numerical sequence in all Work Unit Code manuals. Technical Directive code. The Technical Directive (TD) code is a 12- or 13-character code used to identify a specific TD by type number, revision, amendment, part, and kit number. This code applies to the VIDS/MAF when a TD compliance is documented. The first two characters of Technical Directive codes are listed in an appendix to OPNAVINST 4790.2. Technical Directive Status code. The Technical Directive Status code is a one-character. alphabetic or numeric code used to describe the type of work accomplished. The type of work refers to scheduled maintenance. unscheduled maintenance. and so forth. 1-22