What must happen before changing an FMC flight path?

• A. The captain decides the path unilaterally.
• B. Both pilots must agree the new flight path is correct.
• C. ATC must approve the new path.
• D. The FO must confirm.

Answer: (B)

Coordinated cross-check between crew members is essential when altering the FMC flight path. In a two-pilot cockpit, both pilots reviewing and agreeing that the proposed route, altitudes, and sequencing are correct creates a shared understanding and serves as a critical safety check. This mutual confirmation helps catch errors, ensures the other pilot is aware of the change, and maintains a correct mental model of the flight plan as it will be executed. While ATC clearance is still required for the actual route to be flown, the act of loading a new path into the FMC is a crew responsibility that hinges on both pilots agreeing the change is correct.