What is meant by 'overcentre mechanism' in aviation?

The term 'overcentre mechanism' refers specifically to a system designed to secure parts in place under certain conditions, particularly in mechanisms that require a locking action. This type of mechanism utilizes the principle of moving beyond the center of a pivot point, which creates a secure locking position that prevents movement in either direction.

In aviation, overcentre mechanisms are used in various applications, such as landing gear and control surfaces, where it’s crucial that components remain securely locked during operation, yet can be released or operated when necessary. The design of this mechanism ensures that once it has passed the pivotal point, it is extremely stable and resistant to unintended disengagement, providing an added layer of safety.

The other options discuss different aspects of aviation systems that do not accurately reflect the mechanics of an overcentre mechanism. While signaling systems, emergency releases, and cockpit controls play vital roles in aviation, they do not pertain to the specific function and operational principle that define an overcentre mechanism.