Crew resource management is the effective use of all available resources to operate safely. The resources are human, hardware, and information. A visual observer is one human resource. The remote pilot in command still has final authority and responsibility for the operation. The clearest preflight example is a briefing that covers roles, how you will communicate, and what will make you abort.
All available resources, including a crew of one
The keyed definition is broad on purpose. CRM is not the aircraft's flight-controller software, and it is not a required drone maintenance log. It is how the remote pilot uses whatever can make the flight safer: people, equipment, and information.
Human resources include a visual observer, other crewmembers, and, when you are actually talking to them, pilots and controllers on the frequency. Hardware includes the aircraft, the control station, checklists, and the apps you use to fly. Information includes the weather briefing, NOTAMs, airspace data, and the aircraft manual. A solo remote pilot still has CRM. The resources do not have to be a second certificated pilot. Section 107.73(f) lists crew resource management as its own knowledge area, next to aeronautical decision-making, because the test expects you to manage the flight and not only to recite the altitude limit.
Section 107.19(b) is the authority sentence underneath the teamwork. The remote pilot in command is directly responsible for, and is the final authority as to, the operation of the small unmanned aircraft system. Sharing the scan does not move that sentence onto someone else. How those decisions get made in a changing flight is the subject of aeronautical decision-making.
The visual observer assists. The remote pilot decides.
A visual observer, when you use one, helps the remote pilot and the person on the controls see and avoid other traffic and objects (the §107.3 definition). Section 107.33 requires effective communication at all times among the remote pilot, the person manipulating the controls, and the observer. It requires the observer to be able to see the aircraft the way §107.31 describes, and it requires the three of them to scan for collision hazards and keep awareness of the aircraft's position by direct visual observation.
The question that follows from that setup is about authority, not about eyesight. When a visual observer is used, final authority and responsibility for the operation rest with the remote pilot in command. They do not rest with the observer, and they do not rest with air traffic control. The observer can call traffic, call a hazard, and even call "land." The remote pilot decides and answers for the flight. The duties of that pilot are laid out on the remote pilot in command page.
Ignoring the observer's call is a failure of the communication §107.33 requires. Treating the observer as the new pilot in command is a failure of §107.19. Both mistakes throw away the resource.
The briefing is the preflight example
The clearest preflight example of CRM is briefing the crew on roles, communication, and abort criteria. Who watches the sky, who flies, what word means "land now," and which wind, battery, or traffic event ends the flight: that briefing is the resource put to work before the motors start.
Section 107.49(b) already requires the remote pilot to make sure everyone directly participating is informed about operating conditions, emergency procedures, contingency procedures, roles and responsibilities, and potential hazards. The CRM question and the regulation are describing the same conversation. Skipping the weather check to save time discards an information resource. Ignoring the observer discards a human resource. Neither one is the briefing.
Abort criteria belong in that briefing because they are decided when nobody is rushed. "Land if an airplane calls a two-mile final" is a criterion. Inventing it after the airplane is on a one-mile final is hope.
A two-person roof inspection
You are the remote pilot. A coworker will be the visual observer. Before launch you brief: you will fly and run the camera; the observer will keep the aircraft and the sky in sight and call any manned traffic; if either of you says "land," you land; if the battery warning comes on, you stop the shot and recover. You confirm you can hear each other without the radios being the only link, which is the §107.33 communication requirement in practical form. You also confirm the observer can see the aircraft, not only the controller screen.
During the pass the observer calls a helicopter. You land. The observer does not become the remote pilot by making that call, and you do not keep filming because the shot was almost framed. The briefing did the work. The authority stayed with you.
A solo version of the same job still uses CRM. The human resource may be you alone. The hardware is the aircraft and a written checklist. The information is the METAR, the NOTAMs, and the manual's lost-link behavior. Using those on purpose is the same idea as the two-person briefing.
The trap
The definition trap offers software and a maintenance log. CRM is resources: human, hardware, and information.
The authority trap appears as soon as a visual observer is in the scenario. Help from the observer does not transfer final authority to the observer or to ATC. The remote pilot in command keeps it.
The preflight trap offers speed and silence: skip the weather, ignore the calls. The keyed example is the briefing on roles, communication, and abort criteria.
Use the free practice test on the human-factors items. The crew lessons in the course pair the briefing with the §107.19 authority sentence so the two stay together.