• Ethiopean 737 MCAS crash

    From Aviation HQ@2:292/854 to All on Thu Jan 5 00:56:23 2023
    The French aviation accident board BEA is critical of the final report on the fatal accident involving the Boeing MAX 8 of Ethiopian Airlines in March 2019. According to BEA, their Ethiopian colleagues withheld important information about the actions of the pilots from the report. Earlier, the American NTSB expressed similar criticism.

    Ethiopian flight ET302 crashed into a field shortly after take-off from Addis Ababa on March 10, 2019. All 157 people on board were killed. The main cause was misinformation from a sensor. As a result, the MAX 8's on-board computer instructed the so-called MCAS system to push the nose of the Boeing down four times.

    The two pilots were insufficiently aware of what was going on and could no longer keep the plane in the air. After the accident, it became clear that there was a direct connection to the fatal crash of a MAX 8 of Lion Air in Indonesia in October 2018. Here, too, the Maneuvering Characteristics Augmentation System intervened several times, but in both accidents the pilots did not know how to turn this off because they didn't know it enough. The two accidents prevented the MAX from flying for 20 months.

    In the final report presented at the end of December, the Ethiopian Accident Board EAIB describes in detail how information from a broken Angle of Attack sensor activated the MCAS system, leading to the crash. But like the American National Transportation Safety Board (NTSB), the French Bureau d'Enquetes et d'Analyses pour la securite de l'aviation civile (BEA) also believes that the report ignores important conclusions from the investigation.

    For example, operational aspects and the behavior of the two pilots of ET302 are insufficiently addressed in the final report, "especially in the course of events before MCAS intervened for the first time. As a result, the reader of the report cannot form an exact and complete picture of the events."

    As an example, BEA mentions that shortcomings in the behavior of the pilots, especially during the first phase of the flight, were insufficiently analysed. When the stick shaker activated after take-off because the aircraft threatened to end up in a stall situation, the pilots should have switched off the autopilot and the automatic engine control (autothrottle). Instead of disabling these systems to gain control of the aircraft, they only tried to push the nose down.

    According to BEA, the actions indicate that the pilots experienced enormous stress in a short time after the stick shaker and other warnings went off. The crew hardly communicated with each other, as could be heard on the cockpit voice recorder recording. BEA regrets that entire parts of the recording have not been reproduced in the final report. The French agency concludes that "inadequate actions by the crew and insufficient attention to crew resource management played a role in the chain of events leading up to the crash." The report limits itself to mentioning the entry into force of MCAS as the most likely cause of the accident.

    The NTSB also said immediately after the publication of the final report that too little attention was paid to the behavior of the pilots. The Americans also found that insufficient investigation had been carried out into why the sensor on the disaster aircraft had broken down. The EAIB blames this on an electrical problem, but according to the NTSB it is very likely that the sensor was damaged by a bird strike while taxiing at the airport. BEA notes that this conclusion was already presented to the Ethiopian researchers in September 2019, but it does not appear in the final report.

    --- DB4 - MidniteSpecial
    * Origin: AVIATION ECHO HQ (2:292/854)