During which phases of flight must flight crew members keep their safety belts and shoulder harnesses fastened?

Flight crew members are required to keep their safety belts and shoulder harnesses fastened during takeoffs and landings due to the increased risk and possibility of sudden changes in aircraft movement during these critical phases. Takeoff and landing are often identified as the most accident-prone stages of flight, accounting for a significant percentage of aviation incidents. Therefore, wearing seatbelts and harnesses during these times enhances the safety of crew members by providing them with essential restraint in the event of turbulence, hard landings, or other in-flight emergencies.

While there may be recommendations for wearing safety gear during other phases of flight for enhanced safety, the regulation primarily emphasizes the importance of restraint during these specific critical phases. Ensuring that crew members are properly secured can also aid in maintaining control of the aircraft and performing their duties effectively during these high-stress moments.