What are some guidelines for communication between the Remote Pilot in Command (RPIC) and the Visual Observer (VO)?

Communication between the RPIC and the VO is paramount. The VO must communicate to the pilot any information quickly and accurately, so it is vitally important that the pilot trusts the judgment of the visual observer and acts upon their advice without question. The FAA discourages the use of walkie-talkies, so the VO should be in close proximity to the pilot at all times. There are no specific guidelines for communication, but it should be clear and consistent, and both pilot and visual observer should understand what each command means.