related to technical projects, material, systems, and services. These may include specifications, stan- dards, engineering drawings, associated lists, man- uals, and reports, including scientific and technical reports; they may be in the form of documents, displays, sound records, and digital or analog data. DATA COLLECTION CODES—3M codes used in the MDS. DATA ELEMENT—Data related to an item record. Each data element is identified by a specific data element number to permit its selection for inclusion in output documents, indicating its relationship to other data., and for file maintenance purposes. DATA STORAGE UNIT—A storage medium used by the data storage set for significant maintenance data measured in-flight and after landing. DEFECT—Any nonconformance of the unit or product with specified requirements. Defects will normally be grouped into one or more of the following classes but may be grouped into other classes or subclasses within these classes: DEFECT, CRITICAL—A defect that constitutes a hazardous or unsafe condition, or as determined by experience and judgment could conceivably become so, thus making the aircraft unsafe for flight or endangering operating personnel. DEFECT, MAJOR—A defect, other than critical, that could result in failure or materially reduce the usability of the unit or part for its intended purpose. DEFECT, MINOR—A defect that does not materially reduce the usability of the unit or part for its intended purpose or is a departure from standards but which has no significant bearing on the effective use or operation of the unit or part. DESIGN ACTIVITY—The activity responsible for design, preparation, and maintenance of engineering documents for a given item of military property. The activity may be a government activity, contractor, or vendor. DETACHMENT —A temporary reporting custodian formed with aircraft assigned from a parent squadron or unit. Detachments are established when a squadron deploys one or more aircraft to a ship or base substantially removed from the location of the parent organization; the parent squadron CO feels that it would be impractical to retain reporting custody of the aircraft so deployed. Detachments have the same responsibilities as all other reporting custodians of aircraft. DEVIATION—To depart from established policy or procedures, such as deviation from the NAMP. A specific written authorization, granted prior to the manufacture of an item, to depart from a particular performance or design requirement of a specification, drawing, or other document for a specific number of units or a specific period of time. A deviation differs from an engineering change in that an approved engineering change requires corresponding revision of the documentation defining the affected item, whereas a deviation does not contemplate revision of the applicable specification or drawing. DISCD—(When Discovered Code). A one-character alpha code that identifies when the need for maintenance was discovered. DOD—Department of Defense. DODIC —Department of Defense Identification Code. DON—Department of the Navy—Separately organ- ized under the SECNAV. It operates under the authority, direction, and control of the SECDEF. It is composed of the executive part of DON; including the Office of the SECNAV, the Office of the CNO, and the Headquarters, Marine Corps; the entire operating forces, including naval aviation, of the Navy and the Marine Corps, and the reserve components of those operating forces; and all shore activities, headquarters, forces, bases, installations, activities, and functions under the control or supervision of the SECNAV. It includes the Coast Guard when it is operating as a service in the Navy. DOWNTIME—That element of time during which the item is not in condition to perform its intended function. DPVS—Distributed Plain Language Address (PLA) Verification System. DSF—Data Services Facility—An activity that con- verts document data into machine records and uses these records to produce machine reports and listings. DSN—Defense Switched Network. DTG—Date-Time-Group. E CARDS —Engine Record Cards. AI-7