When are flight crewmembers required to keep their safety belts and shoulder harnesses fastened?

Flight crewmembers are required to keep their safety belts and shoulder harnesses fastened during takeoffs and landings due to the increased risks associated with these phases of flight. Takeoffs and landings are critical points where the aircraft may experience sudden changes in speed, altitude, or potential impacts, making it essential for crew safety to remain secured.

The regulation is designed to ensure that flight crewmembers can maintain control of the aircraft and respond quickly in case of an emergency. By having their restraints fastened during these volatile periods, crewmembers are better protected from injury in the event of turbulence or an unexpected incident.

In contrast, although safety belts and harnesses are important at all times during flight, the requirement to keep them fastened is heightened specifically for takeoff and landing due to the associated risks. Being secured during cruising flight is typically governed by the discretion of the crewmembers and the approval of the captain, as long as safety can be maintained effectively.