| 波音737存在根本设计问题，无法用软件修正 |
| 送交者: 香椿树1 2019年06月03日02:46:24 于 [军事天地] 发送悄悄话 |
|
纽约时报的这篇文章看上去气势汹汹实际上是在替波音公司洗地。 当然媒体扯谎不会让人抓到把柄，总是会把真相藏在假象里， 换句话说就是欺负读者脑残，谁让你没读懂。 报道开头就说波音公司软件设计草率地把多个传感器唤醒的控制系统改成只用一个传感器，是愚蠢行为，给人的印象是只要把多个传感器改回来就万事大吉了。 一个愚蠢的决定，草率的决定修改起来似乎很容易。 但是， 真相藏在细节里。 MCAS出现的原因就是因为换了大发动机之后的波音737在高速飞行的时候不再稳定。 当时的工程师要求修改机翼和气动外形，波音风洞实验觉得做不到， 所以决定用软件打补丁。 波音公司从2012年折腾到2016年，再次试飞的时候发现飞机低速的时候也不稳定， 波音公司这次已经不再考虑修改气动外形和控制系统了， 波音公司的决定是修改软件补丁MCAS。 而修改的方法简直就是草菅人命， 拆掉多传感器的限制， 只用一个传感器， 并且把控制力度增加了5倍！！ 换句话说，波音只用一个传感器不是“愚蠢”的决定， 而是“无奈”的决定， 更是一个“黑心”的决定。 话句话说， 波音737绝对不是修改软件补丁就变得安全， 波音需要得是重新设计飞机的气动外形！ —————————— MCAS Is BornIn 2012, the chief test pilot for the Max had a problem. During the early development of the 737 Max, the pilot, Ray Craig, a silver-haired retired Navy airman, was trying out high-speed situations on a flight simulator, like maneuvers to avoid an obstacle or to escape a powerful vortex from another plane. While such moves might never be necessary for the pilot of a passenger plane, the F.A.A. requires that a jet handle well in those situations. But the plane wasn’t flying smoothly, partly because of the Max’s bigger engines. To fix the issue, Boeing decided to use a piece of software. The system was meant to work in the background, so pilots effectively wouldn’t know it was there. Mr.
Craig, who had been with Boeing since 1988, didn’t like it, according to
one person involved in the testing. An old-school pilot, he eschewed
systems that take control from pilots and would have preferred an
aerodynamic fix such as vortex generators, thin fins on the wings. But
engineers who tested the Max design in a wind tunnel weren’t convinced
they would work, the person said. 【补丁飞机高速时出现飞行不稳定正常情况下需要修改飞机的控制系统和外形， 小修改不管用，才相到用软件强行修公正】 Mr. Craig relented. Such high-speed situations were so rare that he figured the software would never actually kick in. To ensure it didn’t misfire, engineers initially designed MCAS to trigger when the plane exceeded at least two separate thresholds, according to three people who worked on the 737 Max. One involved the plane’s angle to the wind, and the other involved so-called G-force, or the force on the plane that typically comes from accelerating. A
Boeing 737-800 flight simulator. When Mr. Craig simulated high-speed
maneuvers for the Max, it didn’t fly smoothly, so Boeing settled on MCAS
for a fix.CreditAviation-Images.com, via Getty Images The Max would need to hit an exceedingly high G-force that passenger planes would probably never experience. For the jet’s angle, the system took data from the angle-of-attack sensor. The sensor, several inches long, is essentially a small wind vane affixed to the jet’s fuselage. Adding More PowerOn a rainy day in late January 2016, thousands of Boeing employees gathered at a runway next to the 737 factory in Renton, Wash. They cheered as the first Max, nicknamed the Spirit of Renton, lifted off for its maiden test flight. “The flight was a success,” Ed Wilson, the new chief test pilot for the Max, said in a news release at the time. Mr. Wilson, who had tested Boeing fighter jets, had replaced Mr. Craig the previous year. “The 737 Max just felt right in flight, giving us complete confidence that this airplane will meet our customers’ expectations,” he said. But
a few weeks later, Mr. Wilson and his co-pilot began noticing that
something was off, according to a person with direct knowledge of the
flights. The Max wasn’t handling well when nearing stalls at low speeds. 【补丁飞机低速时也不稳定， 再次证明波音737的设计有问题， 整个机体和气动外形有问题， 高速和低速时都不稳定。 高速不稳定还好说， 不飞高速就算了， 低速怎么办？】 In a meeting at Boeing Field in Seattle, Mr. Wilson told engineers that the issue would need to be fixed. He and his co-pilot proposed MCAS, the person said. The change didn’t elicit much debate in the group, which included just a handful of people. It was considered “a run-of-the-mill adjustment,” according to the person. Instead, the group mostly discussed the logistics of how MCAS would be used in the new scenarios. “I don’t recall ever having any real debates over whether it was a good idea or not,” the person said. The change proved pivotal. Expanding the use of MCAS to lower-speed situations required removing the G-force threshold. MCAS now needed to work at low speeds so G-force didn’t apply. The change meant that a single angle-of-attack sensor was the lone guard against a misfire. Although modern 737 jets have two angle-of-attack sensors, the final version of MCAS took data from just one. Ed Wilson, right, with his co-pilot, Craig Bomben, after the first Max test flight in 2016.CreditElaine Thompson/Associated Press Using
MCAS at lower speeds also required increasing the power of the system.
When a plane is flying slowly, flight controls are less sensitive, and
far more movement is needed to steer. Think of turning a car’s steering
wheel at 20 miles an hour versus 70. 【为了赶进度真正的草菅人命来了】 The original version of MCAS could move the stabilizer — the part of the tail that controls the vertical direction of the jet — a maximum of about 0.6 degrees in about 10 seconds. The new version could move the stabilizer up to 2.5 degrees in 10 seconds. Test pilots aren’t responsible for dealing with the ramifications of such changes. Their job is to ensure the plane handles smoothly. Other colleagues are responsible for making the changes, and still others for assessing their impact on safety. Boeing declined to say whether the changes had prompted a new internal safety analysis. |
|
|
|
|
 | |
|
 |
| 实用资讯 | |
|
|
|
|
| 一周点击热帖 | 更多>> |
|
|
|
| 一周回复热帖 |
|
|
|
|
| 历史上的今天：回复热帖 |
| 2018: | 多国纷纷加入北约，中俄面临巨大威胁！ | |
| 2018: | 追求实际效果，特朗普调整新南海战略 | |
| 2017: | 快讯：美防长宣布朝鲜为明确紧迫威胁， | |
| 2017: | 中国首台泵后摆火箭发动机首次试车获得 | |
| 2016: | 揭秘：抗日战场日本武士刀为何赢不了中 | |
| 2016: | 64，坦克履带罪恶滔天！ | |
| 2015: | 林辉：六四屠杀前夜 中共领导人在哪里 | |
| 2015: | 阿基诺访日将中国比作纳粹德国 中方： | |
| 2014: | 拉倒吧。64后中国根本没有什么经济腾飞 | |
| 2014: | 中国航母建造将突破瓶颈 关键技术领先 | |
