A shop-replaceable unit (SRU) or shop-replaceable component (SRC) is a modular component of an

airplane An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, Propeller (aircraft), propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurat ...

ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

that is designed to be replaced by a technician at a backshop. Repair at backshops is known as field-level maintenance or intermediate-level (I-level) maintenance. SRUs are similar in nature to

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 of an airplane, ship or spacecraft (or any other manufactured device) that is designed to b ...

s (LRUs), but rather than being complete functional units, represent component functions, such as circuit card assemblies, of a larger LRU. SRUs are typically assigned logistics control numbers (LCNs) or work unit codes (WUCs) to manage

logistics Logistics is generally the detailed organization and implementation of a complex operation. In a general business sense, logistics manages the flow of goods between the point of origin and the point of consumption to meet the requirements of ...

operations. SRUs can be stocked to allow for quick remove and replace (R&R) operations on their parent LRUs or LLRUs, while also allowing for more extended repair operations at the backshop.

Calibration In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of kno ...

and repair of

United States Air Force The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...

test equipment Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film), ...

is conducted at shops known as precision measurement equipment laboratories.

See also