Fortune teller of Boeing 737' s two air crashes _ Boeing 737' s two air crashes

Previously: What's the connection between the two air crashes?

Boeing 737MAX crashed twice in half a year.

This MAX with the registration number ET-AVJ was delivered to Ethiopian Airlines in October 20 18 165438 10. Boeing 737 MAX is the newest member of the 737 family, which was delivered to the commercial market in May 20 17. Today's incident is its second major accident.

2065438+081October 29th, 18, a 737 MAX 8 plane with 189 people on board crashed in the Java Sea, killing all 189 people on board. (Related report: A passenger plane carrying 189 people crashed in Indonesia! The passengers' belongings salvaged are worrying)

According to the preliminary investigation results, the Indonesian air crash was related to the failure of the aircraft trim mechanism and improper handling by the pilot, and the relevant "patch" policy has been released to other 737 MAX users around the world.

2018165438+128 October, at the press conference held in Jakarta, Indonesia, Nurchayo Utomo, director of the aviation accident investigation department of the Indonesian National Traffic Safety Committee, introduced the air crash investigation to reporters with a model of a Boeing plane. Xinhua News Agency

Weibo, a Boeing company, said that it had been informed of the plane accident report and was paying close attention to the situation.

Boeing said it was very sad about the death of passengers and crew on Ethiopian Airlines Flight 302 (a 737 MAX 8). Express deep sympathy to the relatives and friends of the passengers and crew on the plane and stand ready to support the team of Ethiopian Airlines. Boeing technical team is ready to provide technical assistance under the guidance of national transportation safety board.

It is reported that the number of Boeing 737 MAX delivered to China Airlines has exceeded 60, including Air China, China Eastern Airlines, China Southern Airlines and other major airlines.

The speed of the plane is much higher than the normal speed.

At present, the cause of the air crash is still unclear.

According to the data recorded by @ @Flightradar24—China, the last flight altitude before the plane lost contact was FL086, which was converted into an altitude of 9,027 feet, and the altitude of Addis Ababa Airport itself was 7,625 feet.

Chen Jianguo, a senior captain, analyzed that the published flight data showed that before the plane crashed, the maximum ground speed (referring to the speed of the plane moving relative to the earth's surface during the voyage) reached 383 knots, which exceeded the normal flight speed of the plane. Usually the altitude is below 10000 feet, and the meter speed is 250 knots. However, after taking off, the plane climbed, descended and climbed repeatedly. The altitude was between 7,000 and 8,600 feet, and the maximum ground speed reached 383 knots, which exceeded the normal flight speed of the plane. This data is somewhat similar to the first 737MAX air crash in lion air, which can be attributed to LOC-out of control in the air. But the specific reasons need more data to analyze.

Extended reading

The preliminary investigation report of JT6 10 air crash in lion air released in national transportation safety board, Indonesia on 20 1810 on 29 October shows that the angle-of-attack sensor of aircraft failure was not repaired before takeoff, which may be the main cause of the accident.

It is reported that the angle-of-attack sensor of the crashed plane failed in the last two flights (including JT6 10). After JT38 arrived in Jakarta the night before, a night mechanic repaired some sensors and equipment of the plane, but not the "angle of attack sensor". This sensor is precisely the focus of this investigation, and it is precisely because of the wrong angle of attack data that it triggered the action of MCAS's pressing head.

On October 7th, 201kloc-0/65438/kloc-0 after the Boeing 737MAX air crash in Indonesia, the FAA repeatedly issued the wrong horizontal stabilizer (nose down) trim command in case of wrong AOA data. The emergency airworthiness directive AD20 18-23-5 1 was issued, requiring the operator/owner of Boeing 737-8/9(MAX) to modify the provisions of the Aircraft Flight Manual (AFM) within 3 days after receiving the airworthiness directive, so as to give clear guidance to the crew in terms of operating procedures and model restrictions.

20 18 1 1.9, CAAC officially issued the airworthiness directive CAD20 18-B737- 19, requiring it to be in 20181/kloc-.