Which individual is primarily responsible for the procedure on the flight deck?

The captain is primarily responsible for the procedure on the flight deck. As the highest authority on the aircraft, the captain is accountable for the safety of the flight, the crew, and the passengers. This role includes making critical decisions, overseeing flight operations, and ensuring that all procedures are followed correctly. The captain's leadership is crucial in managing the overall workload and coordinating with the crew, including the first officer and the flight engineer, to execute safe and effective flight operations.

While the first officer and flight engineer have their specific responsibilities and assist the captain, the ultimate responsibility on the flight deck lies with the captain. This includes conducting pre-flight checks, managing in-flight situations, and making final decisions regarding the operation of the aircraft. The role of NO1, if referring to a senior crew member other than the captain, does not carry the same level of responsibility as the captain in terms of overarching command on the flight deck.