What must the pilot in command ensure regarding seatbelts and shoulder harnesses?

The responsibility of the pilot in command concerning seatbelts and shoulder harnesses encompasses ensuring that each person on board is briefed on how to use them. This briefing is crucial for safety, as it prepares all occupants for emergency situations where quick and correct usage of the seatbelts and harnesses may be necessary.

Informing passengers about the proper use of these safety devices helps to create awareness and fosters a culture of safety on board. It ensures that everyone, regardless of their role, knows what to do in case of turbulence or an emergency landing. Briefing occupants is part of a pilot's duty to ensure that safety protocols are followed, to mitigate risks and enhance the overall safety of the flight.

While it’s also important for the pilot to ensure that all passengers wear seatbelts during takeoff and landing, and that equipment is functioning correctly, the core responsibility lies with the communication and briefing aspect, which dramatically influences safety and preparedness among passengers.