During which situation is it essential for flight attendants to ensure passengers have their seatbelts fastened?

It is essential for flight attendants to ensure passengers have their seatbelts fastened particularly during turbulence and landing. These phases of flight are characterized by increased risk due to potential sudden changes in altitude and sudden movements of the aircraft. During turbulence, unstable air can cause the plane to experience abrupt changes in height or direction, which can throw passengers who are not securely buckled into the aisles or against other objects, leading to injuries.

Similarly, during landing, the aircraft experiences various forces that can affect the stability and safety of the passengers on board. Securing seatbelts during this time is crucial as it minimizes the risk of injury from hard landings or unexpected movements as the aircraft touches down.

While seatbelt usage is important at various times throughout the flight, such as during takeoff or when safety announcements are made, the particular emphasis on turbulence and landing is due to the heightened potential for accidents and the effectiveness of seatbelts in mitigating those risks during these specific circumstances.