Airplanes have become the first choice for more and more people to travel, and their safety has always been the focus of attention. When the aircraft encounters an accident and needs to make a forced landing, there are generally two options: land landing and surface forced landing. In people's daily perception, the land is harder, so the risk of forced landing is high, and it seems that the survival rate of the water landing will be higher. After all, we often say that "tenderness is like water", water should be milder, and it stands to reason that the survival rate of forced landing on the water should be higher than that on the ground, but in fact this concept is wrong, why is this?
Those who have watched the American movie "Captain Sully" should have seen the process of how the plane in distress made an emergency landing on the water. The film is based on the true incident of the 2009 US Airways 1549 forced landing, and tells the story of Captain Sully, who successfully made a forced landing to save 155 passengers and crew when his engine failed. However, after such a successful emergency response, Captain Sully was greeted by an investigation by the National Security Transportation Agency. The investigation focused on whether Captain Sully's approach to forcing the water was correct, as it was questioned as more likely to cause a crash and death.
The process of the forced landing of the aircraft on the water
The process of aircraft landing on water generally consists of three stages:
1. The flight process before the collision between the aircraft and the water surface;
2. The response process of the aircraft structure in the event of a collision with the water surface. This process includes two stages: the initial crash and collision phase between the aircraft and the water surface, and the subsequent aircraft surface taxiing phase;
3. The process of floating on the water.
Crash landing process on the water
During the forced landing, the pressure on the fuselage structure is closely related to its mass distribution, flight speed and landing elevation angle.
Why is a crash landing on the water the most dangerous?
First of all, for pilots, a forced landing on water is much more difficult than a forced landing on land. The water surface is not as calm as on land, it has undulations and currents, which are unpredictable for the pilot, so it is impossible to accurately adjust the flight angle, and once the nose or wing of the aircraft first touches the water, the aircraft can tip over at any time.
Secondly, compared to the ground, the undulating water surface will make the structure more fragmented, looser, and more capable of conducting vibrations, and once the nose or wings first touch the water, the aircraft is very prone to partial fragmentation or disintegration. When the speed of the aircraft decreases, the aircraft will "sink" into the water, and if the aircraft has been damaged or disintegrated, it is likely to sink when the speed stops.
Moreover, when the plane plunges into the water, the huge drag causes it to stop immediately, and the force is enough to tear the entire plane apart, crushing everything inside, including the passengers. Therefore, the aircraft must be guaranteed to slide into the water at an absolutely perfect angle in order to gain a short floating time. We know that with the exception of seaplanes, ordinary aircraft are not suitable for floating on the water, so even if the forced landing on the water is successful, the aircraft will sink over time. This means that passengers and crew must hurry up and put on their life jackets and prepare for the escape.
What should I do after a crash landing?
When a ship encounters a difficult situation at sea, the crew on board will use spare lifeboats to escape, but only some of the planes on modern civil airliners have lifeboats prepared for a forced landing on the water just in case. When there is no lifeboat, an emergency slide on an airplane can come in handy.
In order to ensure that passengers can be evacuated quickly during a forced landing, modern aircraft are often equipped with life-saving slides at each emergency exit and cabin door. The life-saving slide is made of nylon adhesive tape, and when not in use, it will be folded and placed in a special box on the door, and marked with the words life-saving slide and other words. When the plane is forced to land, as soon as the cabin door is opened, the life-saving slide will automatically inflate and expand, becoming very elastic. When making a forced landing on the water, the lifeboat can be used as a lifeboat, such as the one in the movie "Captain Sully" where passengers take the lifeboat when they escape.
From this point of view, the risk factor of forced landing on the surface is much higher than that of forced landing on land, and modern aircraft choose to make a forced landing first by choosing the airport, followed by the highway or leveling the ground, and finally the water surface. In the past 60 years, there have only been three successful cases of jet airliners making a forced landing on the surface of the world: on August 21, 1963, the Soviet Tu-124 passenger plane made a forced landing on the Neva River with no one on board, on November 22, 1968, Japan Airlines' DC-8 passenger plane made a forced landing in San Francisco Bay in the United States without any injuries, and the above-mentioned "Captain Sully" On January 15, 2009, US Airways' Airbus A320 aircraft landed on the Hudson River, and all 155 people on board survived, 78 of whom suffered frostbite.
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