How does the No1 communicate "Cabin Secure" to the Captain?

The communication of "Cabin Secure" from the No1 cabin crew member to the Captain is primarily conducted by pressing a button on the flight deck panel. This method guarantees that the information is transmitted directly and efficiently to the flight deck, ensuring the Captain receives confirmation without any potential ambiguities that could arise from verbal communication. Utilizing this method enhances the reliability of the communication process during critical phases of the flight, such as during takeoff or landing, when clarity and speed are vital.

Other options, such as voice communication, sending a note, or using the intercom system, may introduce delays or misinterpretations, which are not ideal in a fast-paced aviation environment. This is why the protocol specifies the use of the button on the flight deck panel for such important communications.