有d post真係慘不忍睹...
https://www.reuters.com/article/ ... s-u-s-idUSKBN1QS2CL
An Ethiopian Airlines 737 MAX 8 bound for Nairobi crashed minutes after take-off on Sunday, killing all 157 aboard and raising questions about the safety of the new variant of the industry workhorse, one of which also crashed in Indonesia in October, killing 189 people.
In a notice, the Federal Aviation Administration said it planned to require design changes by Boeing no later than April. Boeing is working to complete “flight control system enhancements, which provide reduced reliance on procedures associated with required pilot memory items,” the FAA said.
The FAA also said Boeing “plans to update training requirements and flight crew manuals to go with the design change” to an automated protection system called the Maneuvering Characteristics Augmentation System or MCAS. The changes also include MCAS activation and angle of attack signal enhancements.
The FAA said in the notice made public that external reports are drawing similarities between the crashes in Ethiopia and Indonesia. “However, this investigation has just begun and to date we have not been provided data to draw any conclusions or take any actions,” according to the Continued Airworthiness Notification to the International Community for Boeing 737 MAX 8 operators.
U.S. Transportation Secretary Elaine Chao told reporters regulators would not hesitate to act if they find a safety issue.
“If the FAA identifies an issue that affects safety, the department will take immediate and appropriate action,” Chao told reporters. “I want people to be assured that we take these incidents, these accidents very seriously.”
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rickywk 發表於 2019-3-11 14:15
上一次Lion Air事件始終留待印尼當局出最終報告先知真相，初初CVR未搵到前就指住Boeing，但搵到CVR後連大 ...
同意印尼單空難，要等調查報告先有結論。
小弟只係就住NY Times嘅內容，針對呢個系統嘅設計去討論。
仲有樣唔太明嘅地方，係套MCAS想撳低angle of attack防止失速，
點解係揀郁水平尾翼horizontal stabilizer，而唔係升降舵elevator？
Supposedly隻horizontal stabilizer係預長時間(成程機/一個stage)較正用，
短時間嘅操控就用Elevator。
Stall recovery正正係短時間操控，但系統係週較個唔預成日郁而影響大嘅control surface。
仲要無得直接Override。成件事就咁睇落，好怪好唔妥。
個Rationale behind會係個幾值得研究嘅課題。 |
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rickywk 發表於 2019-3-12 11:30
你係指機翼o既Aileron定機尾o既Elevator?
借圖一用
機尾嘅horizontal stabilizer及其上之elevator |
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On Mar 12th 2019 Boeing issued following release with respect to MCAS, Lion Air Flight 610 and Ethiopian flight 302:
For the past several months and in the aftermath of Lion Air Flight 610, Boeing has been developing a flight control software enhancement for the 737 MAX, designed to make an already safe aircraft even safer. This includes updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training. The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading, and provides a limit to the stabilizer command in order to retain elevator authority.
...
The FAA says it anticipates mandating this software enhancement with an Airworthiness Directive (AD) no later than April. We have worked with the FAA in development of this software enhancement.
It is important to note that the FAA is not mandating any further action at this time, and the required actions in AD2018-23.5 continue to be appropriate.
A pitch augmentation control law (MCAS) was implemented on the 737 MAX to improve aircraft handling characteristics and decrease pitch-up tendency at elevated angles of attack. It was put through flight testing as part of the certification process prior to the airplane entering service. MCAS does not control the airplane in normal flight; it improves the behavior of the airplane in a non-normal part of the operating envelope.
Boeing’s 737 MAX Flight Crew Operations Manual (FCOM) already outlines an existing procedure to safely handle the unlikely event of erroneous data coming from an angle of attack (AOA) sensor. The pilot will always be able to override the flight control law using electric trim or manual trim. In addition, it can be controlled through the use of the existing runaway stabilizer procedure as reinforced in the Operations Manual Bulletin (OMB) issued on Nov. 6, 2018.
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A Boeing technical team is at the crash site to provide technical assistance under the direction of the Ethiopia Accident Investigation Bureau and U.S. National Transportation Safety Board. It is still early in the investigation, as we seek to understand the cause of the accident. |
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也許一片海 會重返大洋 也許一片港 會再得芳香 風吹過 堅守這個
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本帖最後由 s3n370 於 2019-3-12 23:48 編輯
rickywk 發表於 2019-3-12 12:37
This includes updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training. The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading, and provides a limit to the stabilizer command in order to retain elevator authority.
波音咁講，即係都表示套系統响調整AoA會過佐龍 |
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也許一片海 會重返大洋 也許一片港 會再得芳香 風吹過 堅守這個
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雖然係咁，但所有 B-reg 既 737 MAX 都係 -8 型號，或者可以解釋佢地點解只係禁 -8
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fb.com/scientisthk2usa/
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S3BL100 發表於 2019-3-13 00:42
雖然係咁，但所有 B-reg 既 737 MAX 都係 -8 型號，或者可以解釋佢地點解只係禁 -8
...
但唔見佢有禁別國嘅737 MAX飛黎喎。
我諗緊係咪空域係軍隊管，所以民航局無權落柯打？ |
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