Safety belts ensure the strength requirements in terms of quality, and bring safety and convenience to passengers. Passengers need to understand why seat belts are used and under what circumstances.
This happens sometimes when we ride in a van. The passenger sitting behind the engine, because there is no seat in front of him, when the car brakes suddenly, he will slip onto the floor. It is conceivable that if a seat belt is fastened to the body, he will not slide off the seat. This is the reason for using seat belts in airplanes, but the situation is more complicated.
When flying at high altitudes, airplanes are not only affected by environmental factors, but sometimes also by the adverse factors produced by the airplane itself. The main manifestation is the front and back passive displacement of the human body caused by the change of acceleration and the violent up and down turbulence caused by the complicated climate.
When an airplane is suddenly subjected to thrust or drag during flight, its speed or direction changes, and acceleration occurs. During take-off, landing and sharp turns, the human body will be displaced due to changes in acceleration. For example, if the airplane is landing too fast and the passenger does not wear a seat belt, the airplane may suddenly decelerate and the passenger may suffer impact damage due to the forward lean. When the plane turns sharply, due to the large centripetal acceleration, unconstrained passengers are easy to fall outward. When general passenger planes fly, the speed is above 500 kilometers per hour, the Boeing passenger plane can reach 900 kilometers per hour, and the supersonic passenger plane Concorde can reach more than 2,000 kilometers per hour. Even during take-off and landing, the speed is 200 kilometers per hour. In case of emergency braking, the consequences will be serious. For this reason, the passenger plane is equipped with seat belts to enable the passengers to move synchronously with the passenger plane to avoid the harm of inertial forces to the passengers.
Another reason for using seat belts is the violent up and down turbulence caused by the complicated climate when the passenger plane is flying in level. In the atmosphere, complex weather changes are numerous. The swirling air flow often moves up and down 10,000 meters in the air, and this is the height of the large jet airliner. Before each voyage, the crew must go to the airport weather room to learn about the weather forecast along the route. However, there are unexpected events. When a wide-body airliner flies at a higher altitude, the sky is often clear, and it is not easy to see the arrival of turbulence with the naked eye. It is the emergence of such clear sky turbulence that makes the driver unpredictable and mind-blowing. These airflows have a certain speed, plus the cruise speed of the passenger aircraft, the relative speed is greater. The strong air current will cause the passenger plane to rise at a speed of 10 to 15 meters per second, or it may cause the passenger plane to descend at a greater speed, disrupt normal flight, and produce violent turbulence. Just like when we were flying a kite, we encountered a whirlwind and couldn't fly a kite. When a passenger plane accidentally enters such a turbulent zone, problems will always occur to varying degrees, ranging from slight vibration or moderate turbulence. In severe cases, the strong turbulence swirling up and down will throw passengers who are not wearing seat belts onto the roof of the cabin and then onto the seat or the floor. The danger can be imagined.
