How does No.1 convey "Cabin Secure" to the Captain?

The procedure for conveying "Cabin Secure" to the Captain involves the use of a specific communication protocol within the aircraft. When the No.1 flight attendant presses 1 and then the ENT (Enter) button on the flight deck door panel, it sends a direct notification to the Captain in a clear and established manner. This method ensures that the message is received promptly and securely, which is critical for maintaining safety and operational efficiency during a flight.

This communication method is designed to prevent misunderstandings and ensures that the information is transmitted directly to the flight deck, which is essential during various phases of flight where cabin security is paramount. Thus, the use of the flight deck door panel for this purpose is standardized in airline operations, enhancing communication efficiency between cabin crew and pilots.