Which entity is NOT required to communicate externally with parties during UAS operations?

The correct choice highlights that bystanders are not required to communicate externally with parties during UAS operations. Although it is important for all parties involved in the operation of the UAS to ensure safety and compliance, bystanders do not hold any formal requirement to communicate with the remote pilot, UAS crew members, or regulatory representatives.

In UAS operations, the Remote Pilot in Command has specific responsibilities that include communicating with others, ensuring safety, and adhering to regulatory requirements. UAS crew members are also involved in communication related to operational tasks and safety management. FAA representatives engage with the remote pilot for regulatory compliance and oversight.

Bystanders, on the other hand, are often members of the public who are not part of the operation. While bystanders may observe and may need to be informed for safety reasons, they do not have a formal role or obligation to communicate during UAS operations, making this answer accurate.