346 people were killed, why did Boeing 737MAX crash?

A Boeing 737MAX plane crashed, killing 346 people. This means that two Boeing 737 MAX passenger planes of Indonesian lion air and Ethiopian Airlines crashed on 20 18129 October and 20 19 March, respectively, killing 346 people on the two passenger planes.

In just half a year, two large-scale serious air crashes occurred in Boeing 737 Max. This is no accident, but there must be deep-seated reasons.

Recently, the US House of Representatives released an investigation report on these two air crashes. The report found that the mistake between Boeing and FAA led to the air crash, which is hard to blame.

The report shows that, on the one hand, there are many problems in the design, manufacture and driver training of the 737 Max, and on the other hand, it is the supervision of Boeing.

First, the design reasons of Boeing 737MAX itself

The plane crashed by Egypt Air is only four months old, which can be said to be a brand-new plane. It doesn't exist for mechanical reasons.

At that time, the plane crashed on the sea six minutes after taking off. According to the French interpretation of the black box of the wrecked plane, the instrument shows that the speed of the plane rose sharply and the altitude dropped shortly after takeoff. This is because the cockpit instrument triggered the stall warning, and the crew increased the speed by reducing the nose to prevent the aircraft from stalling.

However, when the speed rises to about 330 knots, the overspeed warning is triggered again. The confused pilot slowed down again, then triggered the stall alarm, and the altitude of the plane kept falling.

During this process, there will be stall alarm, overspeed alarm and altitude alarm in the engine room for a period of time. Pilots who were not trained in this field panicked in the most critical minutes and the plane crashed directly into the sea.

This is very similar to the symptoms of the accident of the same model 737 Max 8 that happened in lion air on October 20 18. Both of them are related to the automatic stall prevention system, and the pilot does not know how to deal with the alarm.

When Boeing first developed the 737 Max, in order to save fuel for the aircraft, the engine position was slightly moved forward and the nose landing gear was lengthened by 8 inches to design the fuselage. 737 Max achieved a reduction of fuel consumption by 65,438+04%.

However, this airframe design brings a problem that the old 737 doesn't exist: the thrust moves forward, and flying at high elevation angle easily leads to stall.

In order to balance this new problem, Boeing added a new system: when the plane encounters too high angle of attack in manual flight, it will help the pilot to lower the nose.

However, many pilots are not familiar with this system, which may be triggered by sensor error. Judging from the flight curves of lion air and Egypt Air, they all encountered the same problem.

Second, the US Aviation Administration's supervision of Boeing is ineffective.

Every big country has its own aviation management department, which has the function of supervising aircraft design and production. Qualified aircraft will be issued airworthiness certificates, and there are also aviation administrations in the United States.

At first, in order to obtain the airworthiness certificate as soon as possible, Boeing quickly passed the review procedure of the American Aviation Administration by fraudulent means. Before the 737 Max was put into operation, the American Aviation Administration failed to fulfill its responsibilities in the safety approval process.

After 737 MAX was put into operation, many defects were exposed. Some pilots complained about the safety of the plane many times, but the American Aviation Administration turned a blind eye and did not start the investigation procedure.

The most amazing thing is that in recent years, the American Aviation Administration handed over the safety certification to Boeing for self-evaluation. Airworthiness certificates can be issued as long as Boeing recognizes them. What is supervision and supervision?

Seven years ago, an employee of the Aviation Administration warned: Who can guarantee that Boeing will not steal from the inside? These two air crashes, in which 346 people were killed, are the best footnotes of this sentence.