Modular platform components system

Line Replaceable Unit A line replaceable unit (LRU), lower line replaceable unit (LLRU), line replaceable component (LRC) or line replaceable item (LRI) is a modular component that is designed to be replaced quickly at an operating location. An LRU is usually a sealed unit such as a radio or other auxiliary equipment. LRUs improve maintenance operations, because they can be stocked and replaced quickly from on-site inventory, restoring the system to service, while the failed (unserviceable) LRU is undergoing maintenance. Because they are modular, they also reduce system costs and increase quality, by centralising development across different platforms. 

Modularity also enables variety in design by permitting variation in one or more components. This is a way to provide devices in various sizes, or sometimes at various levels of performance. In some cases, this is accomplished by selling the components of the system separately, in others the unit can be thought of as a platform product with several different products, all based on the same system and sharing a large number of elements. See Meyer."... 

---