What mechanism secures the landing gear in the locked down position?

The overcentre mechanism is crucial for securing the landing gear in the locked-down position due to its design, which utilizes geometry to achieve a reliable lock. This mechanism consists of a system of linkages that are positioned in a way that, when the landing gear is fully extended, the links create an angle that prevents the gear from retracting. Essentially, as the landing gear moves into the down position, it surpasses a pivot point, locking it mechanically in place. This ensures that even under the forces of landing or taxiing, the landing gear remains securely extended and does not inadvertently retract.

In comparison, while spring-loaded and hydraulic mechanisms can indeed play roles in landing gear operations, they are more commonly associated with the initial movement of the gear or providing tension; they do not inherently create the locking actions needed to secure the gear in the down position. Conversely, a pneumatic stabilization mechanism is less relevant in this context, as it typically involves air pressure systems that are not directly related to the locking of landing gear. Therefore, the overcentre mechanism stands out as the primary method to ensure that landing gear remains secured in its extended and locked state.