What is the purpose of a locking device?

• A. Affects device calibration
• B. Records maintenance history
• C. Prevents inadvertent movement; ex: lockwire or keeper
• D. Improves thermal insulation

Answer: (C)

Locking devices exist to keep parts securely in place and prevent unintended movement. By locking fasteners, keeps, or brackets, they stop vibration, handling, or thermal changes from loosening connections or shifting components. This helps maintain a reliable electrical path and reduces the risk of arcing, disconnections, or misalignment in equipment. Examples like lockwire and keepers illustrate how fasteners are secured so they cannot back out or rotate. The other options aren’t about keeping things from moving: calibration is about measurement accuracy, recording maintenance history is about documentation, and improving thermal insulation is unrelated to securing components.