Which signal indicates that it is safe to open the MCD after landing?

The signal that indicates it is safe to open the Main Cabin Door (MCD) after landing is when flight attendants confirm the door is ready for arrival. This is an essential safety protocol that ensures the cabin crew has completed all necessary checks and is prepared to safely manage passenger deplaning while still maintaining safety and security procedures.

When flight attendants communicate that the door is ready for arrival, they are signaling that they have assessed the situation outside the aircraft, confirming it is safe to open the door. This includes ensuring the aircraft is secured, that ground services are in position, and that no hazards are present that could jeopardize the safety of disembarking passengers.

The necessity for communication within the crew and the specific call by the flight attendants focuses on their responsibilities and the need for collaboration to ensure a safe environment as passengers deplane. This emphasis underscores the importance of situational awareness and the structured chain of communication among crew members post-landing.