Who is responsible for ensuring the aircraft's airworthiness and operational safety?

The pilot-in-command is primarily responsible for ensuring the aircraft's airworthiness and operational safety. This responsibility encompasses conducting pre-flight inspections, verifying that all maintenance checks have been performed, and ensuring that the aircraft is equipped and configured correctly for the flight. The pilot must also be knowledgeable about the aircraft's systems and operations, and should ensure compliance with all regulations and safety protocols before and during flight.

This does not diminish the important roles of the co-pilot, the aircraft mechanic, and the flight operations manager; however, their responsibilities differ. While the co-pilot assists in operating the aircraft, they do not bear the final responsibility for compliance and safety during flight. The aircraft mechanic performs necessary maintenance and repairs to maintain the aircraft's airworthiness but is not responsible for pre-flight checks or flight operations. The flight operations manager oversees the broader operational aspects but does not personally check each aircraft before flight. Thus, it is the pilot-in-command who holds the ultimate authority and responsibility for the safety of the flight, making this choice the correct one.