Every Part 107 flight has exactly one remote pilot in command, and § 107.19 makes that role the keystone the whole crew is built on. The section requires that a remote pilot in command be designated before or during the flight — so however many people are involved, the operation always resolves to one named person. That person, § 107.19 says, is directly responsible for and the final authority as to the operation of the small unmanned aircraft system. Chapter 2 introduced this authority for the solo pilot; the point here is that “final authority” is exactly what turns a group of people into a crew rather than a committee — the work can be shared, but the decision has one owner.

That responsibility is concrete, not honorary. Section 107.19 loads specific duties onto the remote pilot in command: to ensure the aircraft will pose no undue hazard to other people, aircraft, or property if control is lost for any reason; to ensure the operation complies with all applicable regulations of the chapter; and to have the ability to direct the aircraft to ensure that compliance. Read together, those mean the remote PIC is not merely the person who answers for the flight afterward — they must be positioned, before and during, to keep it safe and legal, and to actually direct the aircraft toward that end.

This is why the rest of the chapter hangs off this one section. In a crew, other people may work the controls or watch the sky, but they do so under the remote PIC’s authority and within the remote PIC’s responsibility. Those duties do not dilute as the crew grows — they concentrate on the one designated person. Whoever holds the role carries the entire compliance-and-safety load; everyone else operates inside it. What follows is how the work distributes across a crew while the accountability, by rule, does not.