Administrative Control Number
A number that looks like and is treated like a real Part Number, but isn’t one. Administrative control numbers can be used to “cover” groups of interchangeable items (see, for example, VICD) or can “cover” groups of items contributing to Make-on-Assembly CI’s. See also the CI Development Cycle (Intermediate).
Allocation
The act of formally designating a relationship between two (or more) things or concepts. For example, we allocate technical requirements to CI‘s when a development specification is authenticated (but not before!).
Allocation Target
The subordinate widget (which may be either concrete or abstract in nature) to which an allocation is made (e.g., a requirement being assigned to a CI).
Change
A formal acknowledgement of intent to alter a baseline while maintaining control over a configuration. Note that the act of establishing a baseline in the first place (as for a new project) is considered the “base change” or “change zero”, which permits all baseline actions to fit into a single database structure.
Change Board
A group of people assigned to assess proposed changes to determine whether they are legitimate and, if so, adequately define the vertical and horizontal integration of associated tasks across a project. A good Change Board can make a project run very smoothly, even if management is idiots. A bad one can make an unrecoverable mess... read more
Class I Change
During the production phase, a change in design that requires prior approval from the Acquisition Customer because it threatens the applicability of the Qualification data on file. A Class I Change is an external change. Contrast with Class II Change. In this context, “threatens” more-or-less means any combination of the following: The revised design might... read more
Class II Change
During the production phase, any change in design that is NOT a Class I Change. A Class II Change is an external change. Contrast with Class I Change. The primary difference in the execution of a Class I Change vs. the execution of a Class II change is one of permission vs. forgiveness (respectively). If... read more
Configuration
1) A relative arrangement of parts or elements. The term can be applied in either the sense of a design or in the sense of an operational situation1. 2) An internally-consistent set of data collectively describing specific known (or desired) aspects of a project, usually a CI or group of related CI’s. The project is usually... read more
Configuration Control
The systematic direction and guidance of development and production to achieve two goals: 1) Correct data are used for each purpose and 2) Particularly during development, the purpose for each controlled data item is known The data include (but are not limited to) designs, specifications, performance analysis, qualification results, and acceptance data.
Configuration Identification
The existential practice of deciding what Configuration Items there will be on a project. This process executes in two distinct modes, depending on the phase of development:
Configuration Item (CI)
An item designated for management by agreement between customer and supplier.
Configuration Item Classification
In the MIL-STD-490 context, CI’s could be differentiated within a single specification (see section 4.1.2) as follows: Types: differences as to design, model, shape, etc. Designated with capital Roman numerals. These were typically used to distinguish differences in performance (function) or other really important features that were critical to different intended end uses. Class: subdivisions... read more
Configuration Management
The practice of applying assets to establish and maintain control over a configuration(2). In this context, "assets" include, but are not limited to, skills, budget, schedule, tools, facilities, and legal instruments with regard to subcontractors and suppliers. read more.
Configuration Management Foundation
I do not intend to try describing all of the Configuration Management processes that I’ve encountered over the years. However, several of them are important to System Engineering, and I’ve drafted a brief introduction to them here. The page isn’t very long, detailed, or thorough. It does, however tie several loose ends together, and sets... read more
Contract End Item (CEI)
An item (a product, as opposed to a “service”) which, when accepted by the Acquisition Customer, results in the Supplier getting paid.
Contractor And Government Agency (CAGE)
The Defense Logistics Agency assigns a unique identifier (the “CAGE Code”) to provide for “…a standardized method of identifying a given facility at a specific location. The code may be used for a Facility Clearance, a Pre-Award survey Engineering Rights, automated Bidders Lists, pay processes, source of supply, etc. In some cases, prime contractors require... read more
Critical Design Review (CDR)
A type of Technical Review held in order to determine a Configuration Item’s readiness to for manufacturing of Qualification Articles. Legacy DoD practices for CDR were according to MIL-STD-1521.
Critical Item
A type of CI that is less significant (in some senses, from some perspectives) than a Prime Item, but more important than a Non-complex Item. In the MIL-STD-490 framework, this class of CI had its own Specification (Spec) format (the “B2” specification) along with explicit rules for when it should be used. The specification was... read more
Dataset
The electronically stored analog of a drawing. All usages and constraints and variations thereof that apply to drawings also apply to datasets.
Deliverable Data
Publications and other information owed to a customer. Generally listed as part of a DIL.
Deliverable Items List (DIL)
A listing of things (products) contractually owed to a customer by a supplier (e.g., CEI’s or documentation), or to a supplier by a customer (e.g., GFE, facility upgrades, or documentation). The DIL can be sub-divided into various categories (e.g., data, material).
Design
As a verb: The act of thinking up (synthesizing) without reference to prior work of the same scope and detail. Modifying something without reference to prior work of the same scope and detail. The act of documenting Engineering intent in a manner sufficiently concrete that unambiguous manufacturing planning can be accomplished to repeatedly produce interchangeable... read more
Detail Specification
In the MIL-STD-490 context, either of the following: A comprehensive set of technical requirements allocable to a given CI without reference to General Specification(s) A set of requirements uniquely allocable to a given CI (sometimes referred to as a “specification sheet”, although they could take book form) plus references to the applicable General Specification(s)
Development Requirement
A technical requirement used to guide (drive) the designers and verification planners during development of a CI. In a perfect world where nothing went wrong, synonymous with Qualification Requirement, except that the final Qualification Requirements might end up not matching the Development Requirements actually used to drive the design. The best ways to use this... read more
Development Specification
A type of detail specification containing the technical requirements for the design and verification of a CI. Contrast with Product/Fabrication Specification.
Deviation
A prior granting of permission to fail before any official attempt (see run for score) to verify compliance with an allocated technical requirement. Use of a deviation avoids giving the appearance of changing the requirement and is, therefore, an important component of an Acquisition Customer’s Pearl Harbor File and (also therefore) much despised by developers.... read more
Directed Design
A condition in which the acquisition customer provides contractual direction with regard to one or more design features in addition to those written into the development specification. Sometimes this happens because the customer wants to make best use of technical thoughts they’ve had; other times it happens because the System Engineering theoreticians try to avoid... read more
Disposition
A decision made with respect to some formally identified, formally managed issue. The issue can be any of many forms (e.g., Review Item Discrepancy or Non-Conformance).
Drawing
An engineering document (which can be in digital form) that discloses, whether directly or by reference, the physical and/or functional requirements for an item. In this business, the term “drawing” is synonymous with “Engineering Drawing” as defined by ASME Y14.24. The alert reader will note that the definition above, which is adapted from the referenced... read more
Effectivity
A type of accession identifier indicating an individual unit (or range) for an End Item, usually assigned during the contractual planning stage for any particular production run or series. Contrast with Serial Number and Line Number: Effectivity represents a contract planning sequence of an order being placed, S/N represents a manufacturing planning sequence, and L/N... read more
End Item
An item (usually a CI) explicitly indicated as completing some specific delivery provision. The provision can involve more than one delivery of the subject item (see Effectivity). See also CEI and PEI.
Engineering Release Unit (ERU)
The impartial third party within an Engineering outfit that holds onto the “released” documentation so that the originating group has no opportunity to violate any of the four rules by re-writing history to hide any errors. The concept of an ERU is intrinsic to demonstrating process integrity, rather than just claiming it. An ERU also... read more
Firmware
Practical, but unofficial definition: data and instructions compiled, or capable of being compiled, into machine readable form such that it can execute without transfer (“loading”) from its on-device storage memory. (i.e., it executes in the same memory address space where it is stored). A computer’s BIOS is a good example of firmware.
Identification
Unfortunately, there are (at least) two senses in which this word is used. They are similar only in the abstract: In the context of manufacturing, the process of marking Part Numbers on parts as they are manufactured. In the context of System Engineering. See Configuration Identification.
Identifying Drawing
A drawing that can legitimately, in accordance with ASME Y14.24, be used to assign a Part Number, and is therefore a mandatory contributor to manufacturing of the Identified part.
Interchangeability
An abstract characteristic of two or more articles, both of which meet the Acceptance Requirements relative to the part’s use as intended by the developer. Interchangeability is the primary criterion for assignment of a single Part Number to a purported specimen of some specific design.
Interface Control Document (ICD)
A formal document characterizing an interface. As a formal document, the ICD typically exists only when two legally distinct organizations must coordinate on the development of items that must coexist to some degree of interest to a contractual customer shared by both organizations.
Line Number (L/N)
A type of accession identifier indicating specific position in a production stream. The line number might, or might not, be indicative of either the order sequence (Effectivity) or planning sequence (S/N).
Lot Number (L/N)
The analog of S/N for products having quality that is dominated (perhaps exclusively determined) by the quality of their bulk material composition or highly repetitive fabrication.
Make-on-Assembly
An item that never exists as a stand-alone P/N, but is only fabricated as its constituent elements are joined into its next-higher assembly.
Make-or-Buy Decision
A design process, occurring early in development, assessing the relative cost effectiveness and feasibility of internal development for an item vs. external procurement of that item. The decision strongly influences how things will go afterwards, bringing substantially different skills and tools into play.
Managing the Configuration
As typically used on real projects, Configuration Management (CM) keeps track of the Engineering data. It creates and manages that data in order to compare what we should be doing (or said we were doing) to what we actually did. CM is central to Engineering's ability to demonstrate the integrity of our development processes. read more.
Model
A system of postulates, data, and inferences presented as a mathematical description of an entity or state of affairs. read more.
Model Number
In common usage, a marketing fiction permitting a single (but not legally binding) description to remain constant for relatively long periods of time. Two items may carry the same model number and yet not be interchangeable. Contrast with Part Number.
Multi-Purpose Drawing
It is legitimate to have a single drawing that acts as more than a just one drawing type. A good example is to start with an existing item from any one of several different suppliers (see Vendor Item Control Drawing), screen the parts to get only the really good ones (see Selected Item Drawing), then... read more
Non-complex Item
In the MIL-STD-490 context, a CI that is not complicated enough or important enough to be considered “critical” (as in “Critical Item”).
Part Number (P/N)
A type of accession identifier uniquely identifying a single stockable item, all specimens of which are interchangeable for the purpose intended by the developer when creating the design. This is the number marked on the part, or on the container if the part’s surface or container if the part’s size or usage precludes direct marking.
Physically Allocated Baseline
A type of baseline in which the architecture is defined by the manufactured product structure. In the legacy, a collection of C-specifications subordinate to a single parent CI.
Prime Item
Anecdotally, a CEI on a Prime Contract and, therefore, the subject of a Type B1 specification in accordance with MIL-STD-490. Lower-order CI’s could also be CEI’s (especially late in the contract, as maintenance items were formally identified), but these (the Prime Items) were considered the heavy-hitters.
Product Structure
The hierarchical organization of Part Numbers comprising one or more individual products, which may (or may not) be related.
Program End Item (PEI)
In certain legacy practices, a CI where both the customer and supplier are within the same organization (therefore, no formal contractual relationship exists, and the lawyers can’t get involved). Contrast with CEI.
Reconciliation
Two Engineers are charged with making calculations: The first adds 2+2, getting 4.1 (he’s probably loaned out to the Marketing department) The second subtracts 4 -2, getting 1.9 (most likely a nervous stress analyst) Recognizing that there should have been a closer dovetailing of the two answers, management executes one or more of the following:... read more
Repair
An MRB disposition for discrepant hardware resulting in a Serial Number that is no longer compliant with the released identifying drawing. Therefore, technically constituting a unique Part Number, usually comprised of the original Part Number plus the number of the directing non-conformance. Repair can be associated with limited use. Contrast with rework. The notion of... read more
Selected Item Drawing
As defined by ASME Y14.24, a Selected Item Drawing does exactly what its name says: it selects certain as-built items from a production stream, rejecting others. This drawing type is identifying because the parts meeting its acceptance criteria are no longer interchangeable with any other parts for the purposes that caused the selected item drawing... read more
Serial Number (S/N)
A type of accession identifier indicating the order in which the manufacturing of an item is planned. Not to be confused with Line Number, Effectivity or a Configuration Item Number.
Specification Tree
A dendrogram of the parent-child relationships between specifications on a project. The graphical paradigm can make it very difficult to show how General Specifications and re-used CI’s relate, so must be interpreted with caution.
Support Equipment
Hardware or software having characteristics not directly needed to comply with requirements that are operationally relevant to the End User, but is necessary (because of the target system’s design features) to deliver, protect, or adapt hardware (or software) during one or more phases of its lifecycle. Support Equipment is often developed in order to adapt... read more
Work Breakdown Structure (WBS)
A hierarchical organization of all the work (effort) required to complete a project. See MIL-STD-881 and follow it. It is conceptually complete and cogent. It is sometimes supposed that a WBS should follow the contractor’s organizational structure (hierarchy of managers), because it is easier to see how the tasks rack-and-stack to the organization. The notion... read more