The sudden fall of the aircraft seems to be due to the fluctuation of air flow, such as micro downburst, strong convection and clear sky turbulence. And the damage of the aircraft fuselage will also cause it to fall suddenly.
The sudden fall of the aircraft during navigation is mostly affected by the air flow, and there are three kinds of air flow that can reach it during the flight.
The first is called micro downburst. When it comes to falling, most people's first reflection may be that something is pressing the plane down in the sky, and micro downburst is the air flow with such properties. It is a local downdraft, which will not only cause the aircraft to fall, but also directly cause it to crash when the aircraft is landing.
The second is called strong convection, which is generated by the vertical movement of air, mainly because the density of air decreases and gradually increases after receiving enough heat from the ground. After rising to a certain height and falling due to high altitude and low temperature, strong convection occurs repeatedly.
The third is called clear sky turbulence. It occurs in the high altitude without clouds, mainly due to the torrent belt. This torrent zone will lead to the uncontrolled descent of aircraft, which is mainly due to the rotation of land rights and the role of solar radiation.
At the same time, if the aircraft is damaged due to accidents during navigation, it will also make the aircraft fall suddenly.