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https://www.wsj.com/articles/ethiop...y-steps-to-disable-737-max-system-11554263276
Ethiopian Airlines Pilots Initially Followed Boeing’s Required Emergency Steps to Disable 737 MAX System
Details of Ethiopian crew’s actions gleaned from preliminary black-box data
Boeing Making Changes to Stall-Prevention System on 737 MAX
Boeing announced it is making changes to how a new a stall-prevention system works on its new 737 MAX aircraft — the same model jet involved in the Ethiopian Airline s crash. WSJ’s Jason Bellini reports.
By
Andy Pasztor and
Andrew Tangel
Updated April 3, 2019 11:53 a.m. ET
Pilots at the controls of the Boeing Co. 737 MAX that crashed in March in Ethiopia initially followed emergency procedures laid out by the plane maker but still failed to recover control of the jet, according to people briefed on the probe’s preliminary findings.
After turning off a flight-control system that was automatically pushing down the plane’s nose shortly after takeoff March 10, these people said, the crew couldn’t get the aircraft to climb and ended up turning it back on and relying on other steps before the final...
https://www.businessinsider.sg/737-...ocedures-preliminary-report-2019-4/?r=US&IR=T
Pilots on the doomed Ethiopian Air 737 Max reportedly followed Boeing’s emergency procedures but still couldn’t stop the plane from crashing
Sinéad Baker, Business Insider US
April 3, 2019
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- Pilots on the Ethiopian Airlines 737 Max plane that crashed in March followed Boeing’s emergency procedures before apparently seeking alternative methods to save the plane, preliminary findings from an investigation have reportedly found.
- Sources familiar with the investigation told The Wall Street Journal that the pilots followed Boeing’s procedures in turning off the MCAS anti-stall software but then turned it back on.
- The MCAS software, designed to point the plane’s nose down if the plane anticipates a stall, is behind the most widely posited theory for what was behind the fatal Ethiopian Airlines and Lion Air 737 Max crashes, which together killed almost 350 people.
- The 737 Max’s approval process has come under increased scrutiny from lawmakers since the crashes. Boeing is working on a software update.
Unnamed sources familiar with the investigation told The Journal that the pilots initially responded to the plane pushing its nose down by cutting power to the automated anti-stall system that is widely thought to have been behind the crash. That apparently didn’t work, The Journal reported, with the pilots later turning the system back on as they seemed to try other steps to control the plane.
All 157 people on board were killed when the plane crashed in Ethiopia soon after taking off from Addis Ababa’s Bole International Airport on March 10.
A failure of software known as the Maneuvering Characteristics Augmentation System has been the most widely discussed theory for both the Ethiopian Airlines crash and the Lion Air Boeing 737 Max 8 crash that killed 189 people in October.
The system is designed to prevent stalls by automatically pointing the nose of the plane downward if the plane senses the aircraft climbing too sharply. Because the system relied on readings from only a single sensor, observers have suggested a faulty sensor reading could incorrectly activate the system.
A passenger-safety instruction card at the scene of the Ethiopian Airlines crash in March. REUTERS/Tiksa Negeri/File Photo
After the Lion Air crash, Boeing and the US Federal Aviation Administration sought to highlight procedures meant to solve any problems with the MCAS software. Those procedures involved disabling MCAS by cutting its power.
Read more: Investigators are close to confirming the lead theory about why the Ethiopian Airlines 737 Max crashed, report says
The Journal said that flight data from the so-called black box, however, indicated that the Ethiopian Airlines pilots did indeed cut power to the anti-stall system. That apparently didn’t work, The Journal said, because they then turned electronic power back on – which reactivated MCAS – while trying alternative methods to raise the plane’s nose.
The flight recorder from the crashed Ethiopian Airlines 737 Max plane. Twitter/BEA
The Journal also reported last week that the preliminary conclusion into the Ethiopian Airlines crash was that the MCAS system mistakenly activated during the fatal flight. This conclusion is subject to change, as investigations into both crashes are ongoing.
Boeing is designing new software for the planes, which have been grounded around the world in the meantime.
The FAA on Monday announced that it expected Boeing to submit the final software fixes for the 737 Max “over the comings weeks” and that it would not approve the software until it was satisfied – a delay that means airlines could keep the planes grounded for weeks longer than expected.
Daniel Elwell, the acting administrator of the Federal Aviation Administration, arriving to testify before a Senate subcommittee in March. REUTERS/Joshua Roberts
Lawmakers are looking at the plane’s approval to fly with increased scrutiny, with particular focus being put on the policy that allows Boeing to partially certify its own aircraft on behalf of the FAA. The acting FAA head, Dan Elwell, told a Senate committee that Boeing partly certified the MCAS software system itself.
Read more: Senate investigating whistleblowers’ claims that government safety inspectors who approved Boeing’s 737 Max plane lacked sufficient training
Whistleblowers also warned of possible serious safety issues in the inspection program for new aircraft, including the 737 Max. They alleged that “numerous FAA employees, including those involved in the Aircraft Evaluation Group (ARG) for the Boeing 737 MAX, had not received proper training and valid certifications,” senators said on Monday.
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https://mil.news.sina.com.cn/jssd/2019-04-04/doc-ihvhiewr3062509.shtml
埃航空难新发现：按照波音要求关闭俯冲系统仍难幸免
埃航空难新发现：按照波音要求关闭俯冲系统仍难幸免
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2018年10月29日，印尼狮航空难给波音公司敲响了警钟，飞机的MCAS系统有问题，很可能由保护神，变成灾星，带领飞机进行自杀式俯冲，为此飞行员和飞机进行了殊死的搏斗，12分钟的飞行历程中，MCAS系统进行了29次俯冲，而飞行员做了34次拉机头动作拯救飞机，最终失败！
在狮航空难事故后，波音也并非没有任何作为，虽然没有全盘审视MCAS系统的设计问题，一直拖着不改，直到埃航空难发生后，全球停飞737MAX，波音公司才慢悠悠出来表示，会认真以安全为重，全面修改MCAS系统。
这么5个月时间之内，波音公司对于737MAX客户的唯一帮助就是发布了一个通知，通知内容就是告知如何在飞行参数可疑情况下，遇到飞机俯冲时候，如何关闭MCAS系统的办法！非常凑巧，埃航是一个传统美国人培养的企业，也认认真真按照通知对飞行员进行了专门的培训。
最新的消息表明，埃航飞行员遇到了MCAS系统抽风，发动了死亡俯冲，由于事先受过专门培训，飞行员也很快把MCAS系统关闭了！但是最后飞机还是坠毁了！
这究竟是为啥呢？
原因是，飞行员发现飞机进入俯冲之后，立即按照要求关闭了MCAS系统，但是关闭系统之后，飞行员发现一个严重的问题，依靠手动操作，飞行员发现遇到很大困难，使用手轮配平，（手轮在下图中间白色圈子内）没法保持正常爬升，最终只好打开MCAS系统，最终继续进入俯冲，机毁人亡告终！
现在的问题来了，为何MCAS系统关闭了，飞机还是没法手工操纵？
问题或许出在MCAS系统设计上，大家都知道MCAS系统是操纵整个平尾的，而飞行员操纵仅仅控制飞机的升降舵，升降舵仅仅占了整个平尾微不足道的一个部分。
飞行员关闭MCAS系统的时候，很可能飞机的平尾水平安定面处于最上角度，向上抬升2.5度，系统关闭之后，平尾就保持这个姿态，没有迅速回到中立0位，这种不正常的姿态生产了强大的低头力矩，使得人工操纵飞机很困难，最终在毫无选择的情况下，埃航飞行员重新打开MCAS系统，最终继续进入死亡俯冲，导致惨剧。
美国多家航空公司多个资深飞行员到波音公司模拟飞行，多次失败，或许也是类似原因，实情如何，让我们等些天就完全清楚，调查报告出现之后再做解读。（作者署名：大水）
Air China is hard to find new: it is still difficult to get rid of the subduction system according to Boeing requirements.
Air China is hard to find new: it is still difficult to get rid of the subduction system according to Boeing requirements.
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On October 29, 2018, Indonesian Lions Airlines was unable to sound the alarm for Boeing. The aircraft's MCAS system had problems. It was likely to be protected by the gods and turned into a disaster star, leading the aircraft to suicide dive for the pilot and the aircraft. In the desperate struggle, in the 12-minute flight, the MCAS system performed 29 subductions, and the pilot did 34 pull-head movements to save the plane and eventually failed!
The lion aviation black box recorded the pilot's hard work and the madness of the plane: the red circle represented the aircraft's 29 automatic dive lions. The air scorpion recorded the pilot's struggle and the madness of the plane: the red circle represented 29 automatic subductions of the aircraft.
After the lion aviation accident, Boeing did not have any action. Although it did not fully examine the design problem of the MCAS system, it has been dragged and left. Until the aviation of Egypt is difficult, the global 737MAX is grounded. Boeing has slowly come out and said that it will Carefully focus on safety and fully modify the MCAS system.
Within such a five-month period, Boeing’s only help for the 737MAX customer was to issue a notice informing them how to close the MCAS system when the aircraft is swooping in the case of suspicious flight parameters! It is very coincidental that Egypt Air is a traditional American-trained enterprise and has specially trained the pilots in accordance with the notice.
Computer simulation, Air Egypt aircraft inadvertently entered the death dive computer simulation, Egypt Airlines aircraft inadvertently entered the death dive
The latest news shows that the Ethiopian pilot encountered a wind gust in the MCAS system and launched a death dive. Due to prior training, the pilot quickly shut down the MCAS system! But in the end the plane crashed!
What is this for you?
The reason was that the pilot immediately noticed that the MCAS system was shut down as soon as the aircraft entered the dive, but after the system was shut down, the pilot found a serious problem. By manual operation, the pilot found that it was very difficult to use the handwheel to trim. (Handwheel In the middle white circle in the picture below) can't keep climbing normally, and finally had to open the MCAS system, and finally continue to dive, the machine is dead!
When the switch in the arrow is closed, the MCAS system stops working and closes the switch in the arrow. The MCAS system stops working.
Now the question is coming. Why is the MCAS system closed and the aircraft still unable to be manually manipulated?
The problem may be in the design of the MCAS system. Everyone knows that the MCAS system is manipulating the entire flat tail, and the pilot maneuver only controls the elevator of the aircraft. The elevator only occupies a negligible part of the flat tail.
MCAS manipulates most of the front of the flat tail, the scientific name is the horizontal stabilizer, and the pilot manipulates the rear elevator MCAS to manipulate most of the front of the flat tail, the scientific name is the horizontal stabilizer, and the pilot manipulates the rear elevator.
When the pilot closes the MCAS system, it is likely that the flat-tailed horizontal stabilizer of the aircraft is at the uppermost angle and is raised upward by 2.5 degrees. After the system is closed, the flat tail maintains this posture and does not quickly return to the neutral position. This abnormal posture is produced. The powerful low head torque makes it difficult to manually maneuver the aircraft. In the end, with no choice, the Air Egypt pilot reopened the MCAS system and eventually continued to enter the death dive, causing the tragedy.
Many senior pilots from many airlines in the United States went to Boeing to simulate flights, and many failures, perhaps for similar reasons. How do we wait for a few days to fully understand the investigation report and then interpret it. (Author's signature: Dashui)
