How much is the relationship between the crash of Egypt Air and the 737max model?

Students majoring in aerospace will answer. Let's start with the conclusion: although it may take several years to investigate the cause of the air crash, the difficulty of this flight in Egypt is probably related to the design of Boeing 737Max, because the MCAS system carried by Boeing 737MAX has huge defects.

What is MCAS system? Why do you need this system? Is there anything wrong with this system? Translated into Chinese, this system is the abbreviation of "mobility enhancement system". If it is changed into something that ordinary people can understand, it is the aircraft driving assistance system.

We know that flying is a very difficult thing, which often depends on people's experience, but sometimes the driver is inexperienced or the accident speed is too fast, which makes people unable to react. At this time, it is necessary to help the pilot control the aircraft through automatic control. For example, many people's cars are equipped with a brake assist system, which can detect whether your brakes are emergency braking, thus helping you to step on the brakes and shorten the braking distance, as shown in the following figure.

For an airplane, one thing is as dangerous as a car brake failure, and that is "stall". To put it simply, when the plane flies, its head is held too high, as shown below. As a result, after a certain critical point, the lift generated by the wing suddenly disappeared, causing the aircraft to lose control. This phenomenon is particularly prone to occur for civil airliners with poor maneuverability.

For example, Boeing 747 crashed at post stall, as shown in the following figure. You will see that the plane just started flying well and suddenly fell to the ground like a broken kite.

Boeing 737Max is a relatively new model of Boeing 737 series. Compared with the old Boeing 737, this latest model has changed a lot, so let's not mention the good side. The downside is that the fuselage has a low center of gravity, which makes it easier for this type of aircraft to "look up", which in turn leads to the stall of the aircraft. So the designer of this plane thought of a way: add an auxiliary control system to make the nose automatically press down. Therefore, a very important function of the MCAS system on the aircraft just mentioned is to automatically reduce the pressure head to prevent the nose from being lifted too high and causing stall.

It stands to reason that the appearance of this auxiliary system is necessary and can also reduce a lot of burden for drivers. However, as long as it is an automatic control system, it has a fatal weakness: it doesn't know how to change it. Whenever the nose is pressed, it is controlled by computer. People can't intervene.

Lion air 20 18, 18129 October Boeing 737Max accidents were caused by the failure of MCAS system, which forced the aircraft to keep in a dive state and eventually led to the accident. The following picture shows the flight data sent back five months ago when the Boeing 737Max passenger plane in lion air had an accident. The blue line is the flying height, and you can see that the flying height fluctuates constantly, up and down.

In fact, the pilot at that time had noticed that the plane began to automatically start the MCAS system and forced the nose down, so he began to "compete" with the control system for more than ten minutes, and finally the enemy could not match the MCAS system, causing the plane to crash. This time, the Air Egypt accident is likely to have the same problem. Flight data show that the aircraft also experienced the fluctuation of flight altitude.

What's wrong with Boeing?

First of all, there is nothing wrong with the original intention of setting up this system. Even in the future, many aircraft will be equipped with such a system to increase maneuverability and make the aircraft safer. But at present, this system is likely to be immature. However, when the system is immature, it is unthinkable that the pilot of the aircraft can completely shut down the system, but it will be restarted repeatedly, and there are huge logical loopholes.

Secondly, Boeing did not mention the existence of MCAS system in the flight crew operation manual, let alone how to deal with such failures when the aircraft system fails, so the pilot probably did not know that the aircraft actually had this function and did not know how to deal with it. When the pilot finds that the plane dives for no reason, it is difficult to deal with it effectively if he does not know the reasons behind it. This is such an important thing that Boeing didn't remind it, let alone conduct targeted training. It was only after the accident in lion air five months ago that this point was urgently added.

Finally, after the lion air plane accident, because Boeing 737Max series is the cash cow of Boeing Company, the complete grounding has a great influence on Boeing Company, so this type of aircraft did not stop grounding, but claimed to carry out "software and hardware upgrade". The upgrade should have been completed in 20 19 1 month, but it was delayed because of the difficulty.

Of course, whether the last Air Egypt accident in March 2065438+2009 was the design problem of Boeing 737Max still needs detailed results, but from the above analysis, Boeing does have many problems, especially the obvious defects of the aircraft itself, which makes people feel incredible.

Therefore, Boeing not only made mistakes in aircraft design, but also made major mistakes in the whole accident handling process. This led to the crash of two planes within five months.