What do you ensure when opening the L1 door of a closed aircraft?

When opening the L1 door of a closed aircraft, it is crucial to ensure that the gust lock engages. The gust lock is a safety mechanism that prevents the door from moving due to wind gusts or pressure changes when the aircraft is on the ground. Engaging the gust lock secures the door in the closed position, ensuring it cannot inadvertently open while personnel are preparing to board or during preflight checks. This is particularly important for maintaining safety on the ground and ensuring that the door opens smoothly without causing injury or damage.

The other choices, while related to door operations, do not specifically address the critical aspect of securing the door against unexpected movement during the opening process. The safety strap, door handle position, and stowing the jumpseat may be important in their respective contexts, but they do not play as central a role in ensuring that the door is safely managed in the face of potential external forces, such as wind.