Boeing 737max has shocked the world several times in a row. Indonesia and Ethiopia crashed less than five months apart, killing 346 people. This situation is rare in the history of modern aviation.
Most man-made disasters are not accidental, but the final performance caused by the superposition of piles of buff, and Boeing 737max is no exception. It can be traced back to a report 1 1 years ago.
That year, the CEO of Boeing Company chose to equip the new model 737MAX with an engine with larger diameter and lower fuel consumption rate to enhance the competitiveness of Boeing aircraft in the world aviation market. This is understandable, but replacing an aircraft engine is not as simple as replacing an automobile engine. Unpredictable risks and component correlation are everywhere.
First of all, only a larger bypass ratio can reduce fuel consumption, which means that the original position of the prototype 737-800 engine is no longer suitable. If it is forcibly installed in the original position, it will cause the engine to be too close to the ground, and it will be easier to inhale debris and damage the engine when taking off. In order to solve this problem, Boeing engineers quickly thought of a simple and economical way to push the engine forward!
It can be clearly seen that the outlet of the external duct of the modified MAX engine is located outside the leading edge of the wing, while the internal and external ducts of the 737-800 are located below the wing. With such a big change, even amateurs will inevitably wonder whether the airflow of the engine will be very different from before, and what impact will it have on the whole aircraft?
Boeing engineers just did some simple computer simulations and then made a hasty decision. After all, time is money. If we spend time and money on wind tunnel tests, we may be fired by our boss.
Then, the problem appeared. When the engine moves forward, the elevation angle is too high when taking off according to the original procedure, and it may crash in an hour, so you need to get off and press the nose to avoid it.
The problem is that the engine has been finalized and it is impossible to modify it. The helpless Boeing engineer continued to pile buff and came up with a genius idea. Two elevation sensors are added to the nose, so as long as the aircraft elevation is detected to be too high, it will automatically bow its head. Perfect!
There is no way to do this, similar to patching. If the fault is verified and trained, it may run safely, but the Boeing team made another fatal mistake and handed over the MCAS system to the Boeing team in India.
Everyone must have seen the news one day after the completion of the Indian dam. In fact, Indians are very smart. They know how to maximize their own interests, but they ignore the bigger overall goal. Boeing India team is no exception. When designing the angle of attack sensor system, it is simply determined that as long as one of them detects that the angle of attack is too large, the automatic nose-down program will be started. In order to prevent human intervention, computer permissions are set higher than manual permissions, and there is no double signal source comparison and fault detection at all. It is said that the Boeing India team did nothing to prevent human intervention.
The Indian director in charge of MCAS is even more whimsical, setting the switch to lower the nose in an inconspicuous corner of the screen, even thinking that others will naturally see it, just press it, without writing instructions or training pilots.
In this way, 737max flew into the sky with one careless, negligent and taken for granted design after another. In the past, pilots of 737 aircraft in Egypt Air and lion air were frightened by the sudden lowering of the nose and tried to pull the joystick. Until the last moment of their lives, it is impossible to notice a button on the screen.
Looking back on the previous things, let's take a look at the 737MAX. The engine is the same, and the position is the same. The only change may be the software system of MCAS, which has been patched for a while and then went to heaven. As for whether we can fly safely, only time will tell us.
In other words, if software can solve the hardware problem, why should people design a brand-new airplane and change the parameters in the program? Quick success! It is these four words that caused the disaster, at the cost of life.