What must the flight deck door be during taxi out, takeoff, flight, landing, and taxi in?

The flight deck door must be closed and locked during taxi out, takeoff, flight, landing, and taxi in to ensure the security and safety of the flight crew and passengers. This procedure is crucial for preventing unauthorized access to the flight deck and protecting against potential threats. Locking the door creates an additional layer of security that safeguards the pilots and the operation of the aircraft.

Maintaining a closed and locked flight deck door aligns with standard aviation security protocols and is particularly important in today’s aviation environment, where the risk of hijacking or other security breaches is a concern. This practice helps ensure that the flight crew can focus on flying the aircraft without the distraction or risk of interference from onboard individuals.