Plane crash

Aircraft crashes happen every few years, which makes people pay attention to aviation accident protection again. What was the cause of the plane crash? This article will introduce you one by one.

First, natural factors.

1, bad weather

There are countless air crashes closely related to the weather, such as the 20 10 Yichun air crash, the Pakistan air crash, and the Polish presidential crash, all of which are accompanied by dense fog. However, air crashes caused by lightning strikes in summer often occur. On August 20 10, the air crash in Colombia was due to the fact that the plane was broken into three parts by lightning while landing, resulting in the death of 1 person and the serious injury of 5 people. According to statistics, there are two air crashes caused by lightning every year on average in the world. However, because the aluminum alloy used as the aircraft shell is a good conductor, when the aircraft is struck by lightning, the current will spread through the aluminum alloy shell, which generally will not have a serious impact on the aircraft. In addition, there are many examples of plane crashes that are caused by cold weather and wind shear during take-off and landing, which is also commonly known as "strange wind".

2. Electromagnetic interference

Why is it dangerous to use a mobile phone on an airplane? It turns out that the navigation equipment on the plane uses electromagnetic waves to determine the direction. After receiving the electromagnetic waves continuously emitted by the ground navigation station, it can measure the exact position of the plane. When the mobile phone is working, it will radiate electromagnetic waves, which will interfere with the navigation equipment and control system on the plane, so that the automatic control equipment of the plane will receive the wrong information, thus making the wrong operation, causing danger and even crashing the plane. In addition to mobile phones, laptops and game consoles also radiate electromagnetic waves, so these devices can't be used on airplanes. In addition, electromagnetic waves generated by astronomical phenomena such as sunspots and northern lights will also interfere with the normal navigation of aircraft.

Second, human factors.

1, pilot control error

This kind of accident is very common. After all, pilots are human beings, and even after professional training, there is no guarantee that they will never make mistakes. For example, the plane crash of Flight 350 on 1982 was due to the fact that the mentally ill captain deliberately turned on the thrust reverser of the aircraft engine, with the intention of crashing the plane, which eventually led to the plane falling into the water and killed 24 passengers. 1985 China airlines flight 006 almost fell into the Pacific ocean because the pilot lost his sense of direction; 1995 the Romanian air crash was caused by the captain's sudden loss of mobility before the plane landed; American Airlines Flight 587 on 200 1 broke a vertical tail due to the pilot's excessive use of rudder; Even more bizarre is the air crash of Aeroflot Flight 593 on 1994. According to the investigation, the reason may be the tragedy caused by the captain Jean 15-year-old son trying to fly.

2. Maintenance error of ground crew.

Including improper loading and unloading of ground crew and illegal maintenance. This is equivalent to putting a time bomb on the plane, and accidents may happen at any time. For example, in 1979, American Airlines 19 1 flight fell off during takeoff due to rough engine handling, which eventually led to the plane crash; In 2000, Alaska Airlines Flight 26 1 lost control during the flight because the tail steering gear was not replaced regularly, causing the passenger plane to fall into the icy Atlantic Ocean. This is really caused by the slackness and irresponsibility of the ground crew, which makes the disaster that should not have happened become a reality.

3. Communication error between pilot and ground crew.

The Tenerife air crash 1977, with the largest number of deaths in aviation history, killed 583 innocent people because of the language barrier between the pilot and the ground crew. Due to the fog at the airport that day, two Boeing 747 passenger planes waiting to take off on the runway could not see each other. Because the pilot of one of the planes could not talk to the air traffic controller, he mistakenly listened to the instructions to start the plane, which led to the two planes taking off at the same time and colliding tragically on the runway. 1997 the indonesian air crash was caused by the air traffic control center causing the plane to go in the wrong direction, resulting in the plane crashing into a mountain and being destroyed. In addition, because the air traffic controller did not clearly report the altitude to the pilot, the expression was vague and violated the procedure. Air crashes emerge one after another.

4. Plane collision

You may wonder why two planes collided in such a big place in the sky. In fact, this kind of accident is still possible. Although there is a lot of space in the sky, people only draw "air corridors" to prevent collisions. A passenger plane can only fly in its own corridor to avoid collision. There are many passenger planes hovering around the airport waiting to land, which is a high-risk area for collisions. Once the plane flies off the route, the consequences will be unimaginable. 1986 Mexican airlines flight 498 was crashed by a private jet over California, USA, and crashed into a residential area. Two planes went to no one lives. 1996 a Boeing 747 and an il 76 collided head-on over Delhi, killing 349 people; In 2002, a Tu 154 was cut in half by the tail of a Boeing 757 over Germany ... The air impact was severe, with a mortality rate of 100%.

Third, hardware failure.

1, engine failure

An engine is a device that provides thrust for an airplane. Without it, an airplane cannot fly. However, in fact, engine failure is far from so terrible. Nowadays, passenger planes have more than two engines. If one engine breaks down, it will generally not cause an accident. Boeing 747 is equipped with four engines, and both engines can land normally when they are broken. Of course not afraid of 10 thousand, just in case. For example, in 2009, the pilot of Inter Milan Airlines Flight 092 accidentally turned off a good engine, which caused a tragedy, or more than two engines failed at the same time, and other extremely unlikely things, so we can only say that there is nothing we can do.

2. Hydraulic failure

On the passenger plane, the hydraulic pipeline connects the pilot's pedal and handle to all the control surfaces, ailerons, lifting surfaces and so on. It can be said that the plane is completely controlled by its hydraulic system. Hydraulic pressure is like a needle tube, pushing in from one end and coming out from the other. Generally speaking, the hydraulic system is very reliable, but there is one disadvantage. Once there is any crack in the hydraulic pipeline, the liquid inside will leak out quickly, and the whole hydraulic system will be useless. A plane with hydraulic failure is like a car without a steering wheel, so hydraulic failure is a terrible accident. In order to prevent such accidents, large passenger planes are generally equipped with three independent hydraulic systems in case one of them goes out of control after failure. However, having said that, all hydraulic failures also occur from time to time. 1985, the tail wing of JAL flight 123 was damaged due to the fall of the rear door, and three sets of hydraulic systems failed at the same time. The plane went out of control and crashed into the mountain area, only four of the 524 people survived. Now there are two technologies to avoid such incidents. The first is the electronic control system, which uses electricity instead of hydraulic pressure to control the control surface of the aircraft; The other is the engine thrust control system, which changes the engine thrust on both sides of the aircraft to achieve lifting and turning. But what is unreliable is that these two systems have not been popularized on passenger planes so far.

3. Mailbox failure

Aviation fuel is very easy to explode when it is vaporized. It sounds terrible, but in fact, there are few accidents directly caused by the explosion of fuel tanks. Because the fuel will not catch fire in flight without external factors, the fire is mainly after the plane crashes. Of course, if the plane really explodes in flight, it will be fatal. Since 1990, there have been three explosions of aircraft fuel tanks in the United States, the most serious of which was 1996, when a TWA Boeing 747 exploded over Long Island, new york, killing 230 people. According to analysis, the accident was mainly caused by the ignition of fuel vapor in the fuel tank by electrostatic spark. Therefore, the US Federal Aviation Administration will require domestic airlines to install fuel tank safety devices on aircraft in the near future to prevent fuel tank fire and explosion accidents. The new safety device will pump nonflammable nitrogen into the fuel tank to reduce the oxygen content in the fuel vapor in the fuel tank. This device can almost completely eliminate the probability of fuel tank fire and explosion.

4, metal fatigue

Aircraft is a combination of a whole set of systems, and any system failure may lead to accidents. The most common cause of failure is metal fatigue. For example, it is like the result of bending the pin repeatedly. When an airplane flies, it will produce vibrations of various frequencies. Coupled with the pressurization/decompression cycle of each take-off and landing, any part is not checked well, and fatigue fracture will occur, which will cause accidents. Amsterdam air crash 1992 was caused by the fatigue fracture of the pin of the engine frame, and two engines fell and planted in residential areas at the same time, killing 47 people; United Airlines Flight 232, 1989, the fatigue fracture of the tail engine blades caused the engine to disintegrate, the hydraulic system failed, and the plane crashed on the runway, killing 296 people 1 1.