What is the order of the chain of command on an aircraft starting from the highest rank?

The correct order of the chain of command on an aircraft, starting from the highest rank, is Captain, First officer, Relief pilot, and International purser. The Captain holds the highest authority and responsibility for the operation of the flight, making critical decisions regarding safety and navigation. The First Officer, who assists the Captain, is second in command and has essential flying responsibilities, supporting the Captain in various operational tasks.

The Relief Pilot is also part of the cockpit crew and can take over flying duties during long-haul flights, as they provide necessary rest periods for other pilots. Finally, the International Purser, while an important role in managing cabin operations, is not part of the cockpit crew, placing them lower in the command hierarchy. Understanding this chain is crucial for maintaining clear communication and responsibility on board.