What mechanism locks the landing gear in the down position?

The mechanism that locks the landing gear in the down position is typically a combination of a spring assist and a J hook. This system is designed to ensure that once the landing gear is fully extended and in the down position, it remains securely locked until it is needed to be retracted.

The spring assist helps to hold the gear into the locked position by providing additional force that keeps the mechanism engaged even under various load conditions during flight. The J hook is part of the locking mechanism that physically secures the gear in its extended position, preventing accidental retraction due to vibrations or other forces experienced during flight.

This system is particularly effective because it combines a reliable mechanical latch (the J hook) with the additional security provided by the spring, ensuring that the landing gear will not inadvertently retract when it is in the down and locked position.