Which of the following is a required document related to crew members?

The correct answer is related to the necessary documentation that crew members must possess, which is their licenses. A crew license, such as a pilot license for a pilot or a flight attendant certificate for cabin crew, certifies the individual’s qualifications to perform their specific duties aboard an aircraft. It demonstrates that they have completed the required training and testing to operate safely and effectively within the aviation environment.

Other options, while related to flight operations, do not represent required credentials specifically for crew members. Weight and balance documents are essential for ensuring the aircraft is loaded within its operational limits but are not specific to crew qualifications. A journey log book tracks flight details and is often managed by the pilot but is not a personal credential. The certificate of registration pertains to the aircraft itself rather than the qualifications of crew members. Thus, the requirement of holding a valid crew license is crucial for legal and safety compliance in the aviation industry.