Final answer:
The nose landing gear (NLG) is held in the up-and-locked position by a mechanical locking mechanism controlled by hydraulic or electrical systems on the aircraft.
Step-by-step explanation:
The nose landing gear (NLG) is held in the up-and-locked position by a mechanical locking mechanism.
This mechanism typically consists of a lock pin that engages with a corresponding hole or slot in the NLG structure, preventing it from moving.
The locking mechanism is often actuated by hydraulic or electrical systems on the aircraft, which release the lock pin when the landing gear needs to be extended or retracted.