DISCD (WHEN DISCOVERED CODE) block. Contains a one-character alpha code to identify when the need for maintenance was discovered. T/M (TYPE MAINTENANCE CODE) block. Contains a one-character alpha or numeric code to describe the type of maintenance action that is being performed. POSIT (POSITION SENSITIVE INDICATOR [PSI]) block. Contains the two-digit PSI of a. component that has been identified in the applicable WUC manual by a double asterisk (**). Position sensitive indicators are used to evaluate performance and/or logistics characteristics between identical components. A PSI identifies location by using a general position code or a specific position code. General position code—A two-digit alphanumeric code that indicates a location by use of plain language. For example, LH/RH indicates left-hand or right-hand installations such as main landing gear components, tires, side-by-side cockpit components, and so forth; and FW/AF indicates fore and aft positions such as tandem cockpit components. UP/LW indicates upper or lower positions such as anti-collision lights or antennas. PR/SC/AL indicates primary, secondary, or alternate positions such as hydraulic components or multiple avionics component installations. Numbers 01, 02, 03, 04, and so forth indicate positions by using a numbering system; for example, rotor dynamic components are numbered as are the positions of fuel nozzles on a gas turbine engine. Specific position code—A two-digit alphanumeric code that indicates a specific location by using alphanumeric sequencing to show the position. FID (FAULT ISOLATION DETECTION) block. The block is reserved for future use and left blank. SAF/EI SER (SAFETY/ENGINEERING IN- VESTIGATION SERIAL NUMBER) block. Contains the locally assigned four-digit safety EI serial number. METER block. Contains the SE meter reading for on-equipment work on G, H, or S type equipment codes (TECS). SE MFGR block—Is left blank. INVENTORY CODE block. Contains a one-digit alpha or numeric code to describe the status of an aircraft during a transaction. Inventory status codes denote the status of the aircraft or equipment at the time of inventory; for example at the inventory conducted because of gain, loss, or a change in material condition reporting status (MCRS). Inventory status codes for aircraft should coincide with the applicable OPNAV XRAY status reportable codes as specified in the Aircraft Inventory Reporting System (AIRS), OPNAVINST 5442.2. There is an inventory status code for inventory only, fully operational, standard depot-level maintenance, special work, special rework at the reporting custodian site, and other (decision to strike, remove from service, bailment, loan, and so forth). 0—Inventory only. Equipment that is inventoried but no mission capability data is collected. These items will only be gained or lost and will require no change in MCRS reporting. This code is used for equipment only and should NOT be used for aircraft reporting. A—Fully operational. Aircraft or equipment in the inventory system that are in a fully operational status. 1—Standard depot-level maintenance (SDLM). Those aircraft or equipment that are en route to, awaiting, or undergoing SDLM. 2—Special work. Aircraft or equipment that are en route to, awaiting at, or undergoing special rework (modification, modernization, conversion, or repair) in the physical custody of a depot-level repair activity. 3—Special rework at the reporting custodian site. Aircraft undergoing depot-level special rework that consists of modernization, modification, conversions, or incorporation of depot level technical directives while in the physical custody of the reporting custodian. Aircraft that receive depot-level repairs while in the physical custody of the reporting custodian remain in inventory code A. 4—Other (decision to strike, remove from service, bailment, loan, and so forth). Those aircraft or equipment that are affected by reasons other than standard or special work. PERM (PERMANENT) UNIT CODE (PUC) block. Contains a six-digit code that identifies the organization that completes the transaction. 4-16