What factor is critical for successful landing gear operation?

Regularly confirming the down and locked status of the landing gear is essential for successful landing gear operation. This practice ensures that the landing gear is fully extended and properly secured before landing, which is critical for the safe touchdown of the aircraft. If the landing gear is not down and locked, it could lead to catastrophic failure during landing, potentially resulting in significant damage to the aircraft and risking the safety of the occupants.

The other factors mentioned are important in their own rights, but they do not directly ensure the safe and effective operation of the landing gear in the same immediate manner. Proper visual clearance can aid in avoiding obstacles during landing, and frequent maintenance checks are vital for the overall health of the aircraft's systems. However, these actions do not confirm the landing gear's position at the crucial moment before landing. Using automatic systems exclusively may lead pilots to become complacent, which could cause them to neglect the manual verification that is necessary for ensuring the landing gear is in the correct position for landing.