In Part 121 operations, who is primarily responsible for preflight planning?

In Part 121 operations, both the pilot-in-command and the dispatcher share the primary responsibility for preflight planning, making this answer the most accurate.

The pilot-in-command is ultimately responsible for the safety of the flight and must ensure that the flight is planned according to various factors, including weather conditions, route, fuel requirements, and any operational limitations. This includes conducting a thorough review of the aircraft's performance data and the expected flight environment.

On the other hand, the dispatcher plays a crucial role by providing operational support and conducting in-depth analyses relevant to the flight. This includes generating flight plans, monitoring weather updates, and ensuring that all regulatory and safety factors are considered. The dispatcher serves as a critical resource from the ground and allows the pilot to focus on the operational aspects of the flight.

The collaborative effort of both roles ensures that all aspects of flight planning are covered, enhancing safety and compliance with regulations. Thus, recognizing the shared responsibility between the pilot-in-command and the dispatcher is essential in understanding the dynamics of flight operations under Part 121.