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737 Max Second Deadly Crash / China Grounds Plane / Others Follow Suit / FAA Finally Grounds Jet



  • edited March 2019
    Boeing 737 Max Software Fix And Report On Fatal Crash Expected This Week

    NPR reports that "Boeing says it has a software fix ready for its 737 MAX airplanes that will be unveiled to airline officials, pilots and aviation authorities from around the world Wednesday".

    Following are selected excerpts from the NPR news release:

    "Meanwhile, those crashes and the relationship between Boeing and the federal agency charged with regulating it will be discussed at a U.S. Senate aviation subcommittee hearing on Wednesday. Scheduled to testify are the heads of the Federal Aviation Administration and the National Transportation Safety Board, along with the Transportation Department's inspector general, who is investigating how the FAA went about certifying the 737 MAX as airworthy, and whether regulators relied too heavily on Boeing's own safety assessments in their review."

    "Boeing officials say the company has completed developing software upgrades for MCAS aimed at preventing such occurrences in the future. The system will no longer act repeatedly in forcing the nose of the plane and will act just once if detecting the plane entering an aerodynamic stall. And the MCAS system will rely on data from the two angle of attack sensors on the plane, instead of just one.

    In addition, a warning light that alerts the pilot when the angle of attack sensors disagree will become standard instead of being a more expensive option for airlines to purchase, and it will be added to the entire fleet of 737 MAX aircraft for free."

    "Regulators in Canada, Europe, China and other countries say they will no longer rely on FAA data and will conduct their own tests of the MCAS software updates before allowing Boeing's 737 MAX planes in the air again. As a result, some experts say it could be months before the airplanes are allowed back into service."

  • A detailed article in this morning's Wall Street Journal provides comprehensive additional information on the 737 Max problems.

    Here are excerpts from that excellent report:

    "Boeing needed the redesign of its crucial 737 jetliner to go swiftly and smoothly, so it pursued a path that reduced regulatory scrutiny and accommodated its biggest customer by requiring as little new training for pilots as possible."

    "Pilots flying the 737 MAX, which entered service in 2017, received no training on a new stall-prevention system and saw almost no mention of it in manuals, according to pilots and industry officials. Most would get no visible cockpit warnings when a sensor used to trigger the system malfunctioned, and they had no access to simulators that could replicate the kinds of problems believed to have downed Lion Air flight 610 in October."

    "The MAX planes entered service before the first flight simulators were even ready for use by airlines, according to airline executives, and the few that have now been introduced can’t replicate the malfunction the Lion Air crew faced. The simulators are set to be enhanced to allow pilots to practice dealing with such failures, though the upgrade could be months away."

    "Numerous pilots and safety experts interviewed by The Wall Street Journal said that in practice, amid the chaos of an aircraft lurching into a steep dive with emergency warnings blaring, it is unrealistic to expect pilots to recognize what is happening and respond almost instantaneously."

    (All bold emphasis added in the above excerpts.)
  • edited March 2019
    Boeing: "Sure, we could have built it to be safe from the start. If you wanted a SAFE airplane, you (airlines) should have paid for the optional equipment."
    Boeing = sac of pus.
  • A lousy 10k or so "extra" for the safety indicators. On a multi-million dollar aircraft.
  • edited March 2019
    No doubt the 737Max has problems. Let's hope they are fixable ... and, in short order. I'm also thinking the plane needs to go through a recertification process and not just a we fixed the problem process. Even if our FAA gives it air worthy certification other countries must as well before it can fly globally. To have a third plane go down with these same issuses would be ... Well, not good.
  • A current Washington Post article from their Business section:

    "Boeing, initially defensive, now ‘humbled’ by 737 Max crisis"

    Selected excerpts:

    • "In the weeks after a Boeing jetliner crashed in the Java Sea near Indonesia last year, the manufacturer defended the plane’s safety features and publicly resisted calls to make changes to its system and pilot training procedures."

    • "Boeing’s shift in tone... reflects growing pressure on the company’s bottom line as its fleet of jetliners sits idle at airports. It also comes as airlines that have placed orders for hundreds of additional 737 Max jets begin to question those investments."

    • "Boeing is responding to rising public concerns about its Max planes in an effort to save the company’s image and prevent the loss of more business"

    • "Boeing [is now] working to drum up support for a flight control system overhaul and a new pilot training regimen that it hopes will allay safety concerns raised by pilot groups and others."

    (Some of the above excerpts were lightly edited for brevity.)
  • Boeing Scrambles To Restore Faith In Its 737 Max Airplane After Crashes

    A current NPR report is describing software fixes and other improvements for the 737 Max fleet in the greatest detail yet this week. Among the changes Boeing detailed to reporters, the airlines, regulators and pilots Wednesday:

    • The MCAS system relies on data from two sensors instead of just one to determine whether the plane is in danger of aerodynamic stall.

    • If MCAS is activated, the system will act only once instead of repeatedly forcing the nose of the plane down.

    • Pilots will be able to override the automated system by pulling back on the control column.

    • Warning lights alerting pilots to a problem with the sensors will become standard instead of a more expensive option.

    • Boeing will enhance training for pilots on MCAS, incorporating all of the changes it makes, once approved by regulators.

    The company has been developing these changes in consultation with airlines, pilots and the FAA, and Boeing says the modifications have been undergoing rigorous testing, with engineers looking for potential flaws and malfunctions.

    "We're optimistic but we're still cautious," says Capt. Jason Goldberg, a 737 pilot for American Airlines and a spokesman for the pilots union. He says some of his members have tested out the software modifications in a simulator.

    "We really believe that the software fixes have to be thoroughly vetted by the regulatory agencies and by the pilots who are going to be flying these aircraft. We don't want to see this process rushed or fast-tracked."

    (The above are selected excerpts from a comprehensive and detailed NPR report.)
  • Investigators Believe Boeing 737 MAX Stall-Prevention Feature Activated in Ethiopian Crash

    A current article in The Wall Street Journal is reporting that "Officials believe a suspect automated flight-control system activated before a Boeing 737 MAX nose-dived into the ground in Ethiopia.

    The emerging consensus among investigators... is the strongest indication yet that the same automated system, called MCAS, misfired in both the Ethiopian Airlines flight earlier this month and a Lion Air flight in Indonesia, which crashed less than five months earlier.

    Boeing... outlined its planned overhaul of the MCAS system to make it less aggressive and more controllable by pilots. The changes include an added layer of protection: Instead of relying on a single sensor indicating the angle of the plane’s nose, MCAS will rely on data from both of the plane’s sensors. As part of the fix, the FAA also will mandate certain cockpit alerts about incorrect sensor data.

    Mike Sinnett, [Boeing] vice president of product strategy, said Wednesday the plane maker had “complete confidence that the changes we’re making would address any of these accidents.”

    Roddy Guthrie, the 737 fleet captain for American Airlines Group Inc., said that with the MCAS fix, “They’ve put some checks and balances in the system now that will make the system much better.”

    However, Boeing’s 737 MAX will remain grounded around the world until the FAA and other aviation regulators certify the software fix and crews are trained on the revised system. That process could stretch for months in some countries, regulators and safety officials have said."

    (These short excerpts from the Wall Street Journal article were lightly edited for brevity.)
  • Following are selected excerpts, edited for brevity, from a lengthy and comprehensive article in yesterday's Wall Street Journal.

    In the aftermath of a Boeing MAX jet crash in Indonesia in October, much of the American aviation industry—the plane maker, the FAA, U.S. airlines and their pilots—closed ranks to reassure the public the model was safe to fly.

    “Our pilots are trained to deal with any of these issues,” United Continental Holdings Inc. Chief Executive Oscar Munoz said at a March 7 aviation event in Washington. “Just fly the darn airplane—that’s what they’re taught.” Three days later, a 737 MAX flown by United code-share partner Ethiopian Airlines nose-dived into the ground after six minutes aloft, an eerie replay of Indonesia’s Lion Air crash.

    The crisis brings into sharp relief a major vulnerability for Boeing: As the Chicago-based plane maker increasingly depends on business from emerging markets hungry for air travel, it must focus on safeguards not only aimed at U.S. aviators but also engineer planes with automated systems that new, relatively inexperienced pilots around the world can safely operate.

    Why is this "a major vulnerability for Boeing" but not for Airbus?

    In adding larger, fuel-efficient engines, Boeing had to tweak the plane’s design and add the MCAS system to prevent potential stalls created by the revised placement of the engines. The idea was to make the 737 MAX handle like its predecessors, part of a goal to minimize additional training costs for airlines buying the new plane.

    Two U.S. carriers, American and Southwest Airlines Co. , had already added some of the safety features under discussion, such as an alert that would signal when two sensors disagree. American, whose planes have had these features for years, also had displays to show the specific sensor measurements. Southwest opted to add that feature after the Lion Air crash. But these features cost around $50,000 to add, according to government documents, and many budget airlines overseas didn’t incorporate them.

    A day after the Ethiopian crash, Boeing publicly announced the final details of its planned software update that went beyond what many industry officials familiar with the discussions had anticipated.

    The changes to the stall-prevention system that automatically pushes down a plane’s nose and can override manual pilot commands, mark a major shift from how Boeing originally designed the feature in the aircraft. The goal of the fix now is to make the system... more controllable by pilots and unable to misfire if it receives incorrect data from a sensor. Earlier proposals envisioned far fewer changes, according to one person briefed on the process.

    (Underlining emphasis added.)
  • edited April 2019
    @Old_Joe - Re your “Comment: Why is this "a major vulnerability for Boeing" but not for Airbus?”

    You nail that on the head later in your passage. As we’ve suspected, that last upgrade (to those larger heavier fuel efficient engines) caused the (currently dysfunctional) MCAS system to be added. Similar to “The camel: A horse designed by committee” analogy I offered up earlier. This old workhorse has had modifications on top of modifications over its 50-year + lifetime. Was a much smaller, lower-to the-ground plane when introduced back in the 60s. Most of those upgrades made it a better (and more profitable) aircraft - but they may have pushed the envelope a bit too far. The A320 it competes against isn’t a new plane either - but probably a 20-year newer design than the 737 - hence an easier plane to modify / upgrade.

    None of this is pretty. We all want the U.S. to be the leader in world aviation. But call it what it is - a mess for Boeing.

    When it rains it pours.

    Air Canada expects 737 Max to be grounded until at least July.

    Boeing confirms software upgrade will be delayed.

    U.S. military halts delivery of Boeing tanker.

    Boeing suffers more delays in crewed spacecraft program.

    This is big. They’re competing head-on with SpaceX who has already had a highly successful test of similar spacecraft. Have to say - I’ve read widely on this program (and the competition) and the consensus among those who should know (aviation experts, engineers, etc.) seems to be that SpaceX has a much better and more advanced spacecraft. Too soon to tell for sure. One small advantage Boeing has is that their craft will land on terra-firma (vs water for SpaxeX).

    One play on the 737 story might be to short Southwest. At some point in the not too distant future they’re going to have to transition out of their 100% reliance on the 737 into something newer. That spells some major additional expense in retraining flight crews and maintenance people, upgrading facilities, etc.
  • @hank- Thanks much for the additional info. It's an excellent point re future upgrades... what is Southwest (and others, of course) going to buy? There's nothing currently in the Boeing pipeline. I'm not sure if Airbus has something of a newer and competitive configuration either. That's a good subject for some in-depth financial research.

  • edited April 2019
    Following are selected excerpts from a current comprehensive article in the Washington Post:

    More than five months after a brand-new Boeing 737 MAX 8 commercial jet went down in Indonesia, the manufacturer is still working on a software fix for the plane’s flight-control systems. Boeing’s vice president of communications emphasized that the company is proceeding carefully to ensure regulators are satisfied.

    Boeing started working on the software fix several months ago and has been testing it in updated jets. Last week Boeing executives unveiled a version of the new flight-control system, designed to prevent MCAS from overreacting, and new visual alerts to make pilots aware of potentially dangerous situations.

    The update would limit how quickly the stall-suppression system could tip down the nose of the plane, giving pilots more time to respond if MCAS is activated. It would [also] alert pilots when the plane’s external sensors show different readings.

    “We went through a process of developing the software, deploying it, testing it and going back to our requirements ... it took this amount of time to get it right,” a Boeing official speaking on the condition of anonymity told reporters at a briefing Wednesday in Renton, Wash. “We didn’t rush it, because rushing it is the wrong thing to do in a situation like this.”

    With the new flight-control software, MCAS would disengage if there is a major discrepancy in the sensor data the system relies upon to tell if the plane is nearing a stall, the company has said.

    “Right now, we know what we are worried about,” said a professor of aeronautics at the Massachusetts Institute of Technology. “One of the challenges is, when you start messing around with software, you have to make sure you haven’t created some other problem.”

    Two former Boeing engineers who worked on automatic flight-control systems for Boeing told The Washington Post that the changes would probably require Boeing to prove that the plane could be handled safely without MCAS, including at landing.

    “What if you’re landing without MCAS?” asked one engineer, who spoke on the condition of anonymity because his job still requires him to interact with Boeing. “Would you have to increase your speed a few knots for safety? Would anything change in an aborted landing procedure?”

    Comment: Here's an interesting bit of information that hasn't been covered in any of the previous posts in this thread:

    Peter Lemme, a former Boeing engineer who helped designed flight-control systems for the 757 and 767, said he was glad that Boeing has said it would disengage the system if there is a discrepancy in sensor data. Unlike other models of newer Boeing jet liners that have three Angle-of-Attack sensors to gauge a stall, the 737 Max jets have only two.

    “If one’s wrong, you can’t take the average of two, and you can’t use the good one, because the computer doesn’t know which one is right,” Lemme said.

    Lemme said Boeing also seemed to have underestimated the hazard that the new flight-control system can cause when it is fed faulty data, saying the company is probably taking extra time to now ask, “what aren’t we thinking about?”

    Comment: I wonder how much Boeing "saved" with only two sensors?

    (The above excerpts have been significantly edited for brevity. Underlining emphasis was added.)
  • edited April 2019
    Re: “What if you’re landing without MCAS? Would you have to increase your speed a few knots ...?”

    @Old_Joe - Gets complicated ... Doesn’t it?

    Here’s a good article. The excerpts speak for themselves.

    “It is becoming increasingly clear that the new model 737s were rushed into service without the level of pilot training that normally accompanies the introduction of new or redesigned aircraft.”

    “New revelations also indicate that Boeing, the commercial carriers, the Federal Aviation Administration (FAA) and the pilots unions were all involved in the process by which safety and training corners were cut in the interests of reducing costs and accelerating production and sales, so as to gain market share and profits at the expense of Boeing’s chief competitor, European-based Airbus.”

    “Greg Bowen, the training and standards chair at the Southwest pilots union, (was quoted) as saying the senior leadership at Southwest told him the engineering data necessary to design software for pilot training simulators was still being finalized ‘right up until the plane was nearly completed.’ ‘They were building the airplane and still designing it,’ Bowen said. ‘The data to build a simulator didn’t become available until about when the plane was ready to fly.’

    OJ - I remember back 20-25 years ago when the 777 was undergoing certification testing. No rush with that one. I think they did about everything except fly it into a mountain to make sure it was safe.
  • @hank- Yep. I wonder how many more roaches will be crawling out of the darkness? Sounds like all hands thought that a "cheap and dirty" 737 rework shouldn't be a big deal. How "cheap" it will turn out to be remains to be seen. But "dirty"? No question there.
  • Pilots Split Over FAA Chief's Claims On Boeing 737 Max Training

    An NPR business report today describes a disagreement between the FAA and a major pilot's union regarding the much-maligned Maneuvering Characteristics Augmentation System (MCAS).

    In response to Sen. Ted Cruz, R-Texas, chairman of the aviation subcommittee of the Senate Commerce Committee, Daniel Elwell, the acting chief of the Federal Aviation Administration testified that MCAS " is accounted for in the training," and went on to say that the real problem the 737 Max pilots faced was something called runaway pitch trim.

    That problem concerns the pitch, or angle of the plane's nose in the air. Every aircraft has systems for adjusting the pitch. When a plane is cruising it's usually controlled by autopilot. But if the pitch trim system is out of control, pilots are trained to take over and fly the plane manually. Elwell emphasized that all pilots should know how to do that. "You're not fumbling through books, it's a time-critical procedure, and you go to that," he told lawmakers.

    The 737 Max is different, though. MCAS is meant to help pilots prevent a stall by pushing the nose of the plane down if it senses the plane is flying at too steep of an angle.

    Pilots can override MCAS. But a lot of pilots say they didn't know the software existed until after the Lion Air crash. They say the manual did not explain it or provide explicit instructions on how to disable it. Capt. Jason Goldberg flies for American Airlines and is a spokesman for its union, the Allied Pilots Association. He disagrees that pilots got enough training to handle MCAS.

    "I hate to be in a position to contradict Acting Director Elwell, but in this case the statement is not correct." Goldberg says it's true that pilots train to overcome pitch trim problems, so they can get the plane's nose flying at the correct angle if the system goes haywire. But an MCAS malfunction on a Boeing 737 Max creates a host of other problems and they're all distracting.

    "You would have the stick shaker, which [activates] a rather violent aggressive shaking of the control column," Goldberg says. "You would have the appearance of unreliable airspeed. You would have a number of warnings that don't immediately or intuitively give the impression of a pitch trim problem."

    Even among pilots of major U.S. airlines, Elwell has triggered a stark difference of opinion:

    "We have been trained on how to handle the mishap that occurred in at least the Lion Air jet that we know about," says James Belton, a United Airlines pilot and spokesman for the Air Line Pilots Association. He says the manual described how a 737 Max will respond in the kind of scenario that would trigger MCAS, even if it did not name the software outright. Further, he says the FAA issued a directive after the Lion Air crash that provided clearer instructions. Belton says U.S. airlines have flown the 737 Max for more than 100,000 hours, including some 23,000 hours at United, without a problem.

    "I can't really comment as to the training that they get overseas, but I know here in America ... we have not seen one data point saying that we had a performance or a maintenance issue with it," he says.

    ■ ■ ■ ■ ■
    Comment: The following would seem to contradict UAL Captain Belton:

    On March 13 NPR reported that "In two cases, pilots flying in the U.S. late last year had their planes pitch down unexpectedly after departures. Both times, the crew disengaged the autopilot and were able to keep flying safely. In a third report, a pilot complained that the Boeing 737 MAX's flight manual was inadequate and 'almost criminally insufficient.' "
    ■ ■ ■ ■ ■

    Elwell's claim that pilots were prepared for the MCAS has raised eyebrows among some training experts:

    "I find it surprising that a system that affects the pitch control of an aircraft of any description is not brought to the attention of the people that are going to be flying it," says Dai Whittingham, chief executive of the United Kingdom Flight Safety Committee. Whittingham says pointing to the pilots' training as a possible reason for the two crashes is "deflecting responsibility from where it properly lies" — with Boeing and the FAA.

    He says he believes U.S. pilots were just as vulnerable to an MCAS malfunction as their overseas counterparts. "I think it would have been possible for an American pilot to have crashed the 737 Max if they had not been able to diagnose the problem,"

    (Selected excerpts above, edited and abridged from NPR reports, are indicated by italic text.)

  • Old_Joe said:

    Elwell's claim that pilots were prepared for the MCAS has raised eyebrows among some training experts:

    "I find it surprising that a system that affects the pitch control of an aircraft of any description is not brought to the attention of the people that are going to be flying it," says Dai Whittingham, chief executive of the United Kingdom Flight Safety Committee. Whittingham says pointing to the pilots' training as a possible reason for the two crashes is "deflecting responsibility from where it properly lies" — with Boeing and the FAA.

    I don't know if it's an apt analogy (all I know about airplanes is from SeatGuru), but this is reminding me of the introduction of ABS in cars. Suddenly "piloting" changed.

    Instead of requiring the driver to handle a skid by pumping the brakes, a computer automatically takes over and the driver is supposed to continuously press the brake pedal.

    Imagine if this change had been made without a lot of publicity and instructions to drivers.
  • edited April 2019
    @Old_Joe- Thanks for the update. News is coming fast and furious now.

    Much on ABC tonight on how those unfortunate pilots on the last downed bird switched MCAS off as trained - but “inexplicably” switched it back on when they weren’t able to properly trim the plane with it off. Turning it back on than sent the plane into a fatal plunge. Also - a bird-strike during take-off is now seen as the likely cause of the damage to the angle of attack sensor.

    Interesting that both fatal crashes occurred right after take-off. From what you’ve just reported, it seems to me that this problem with MCAS has been occurring much more frequently than we had been led to believe. The difference is that when a plane is at cruise altitude there’s time for the crew to react correctly (override the system). But those hapless (albeit inadequately trained) pilots on both doomed flights right after take-off - with so much going on navigation-wise and precious little altitude to work with, didn’t stand a chance.

    FWIW - Boeing’s CEO today took a “demonstration ride” on a 737/Max outfitted with the latest software upgrade to demonstrate to the public that the plane is now safe to fly on. (Can’t wait to step aboard one.)

    @msf - nice analogy to brake pumping. (I continued “pumping” for many years thereafter.):)

    Hmm ... These big planes are in a different league. Have been pretty much fully automated for the last 30 years. Pilot‘s pretty much inside a glass jar. “Directions: Break glass and pull out pilot in an emergency.”

    Takeoffs often utilize pre-programmed thrust settings - but are not fully automated. There’s still some hands-on during most landings - although many planes are capable of automated landing (within strict limitations).

    Video - 737 fully automated landing at EHBK - Maastricht Aachen Airport, Beek, Netherlands.
  • Howdy folks,

    What I still fail to understand is the pure arrogance of the management at Boeing. From the beginning they blamed the pilots in a - shall we say, most condescending manner. Sorry but saying RTFM to the relatives of several hundred dead people doesn't get it. Cripes, it's like how not to handle a crisis 101.

    And BTW, the FAA . . . .

    and so it goes,


  • @Rono- Your post prompts a reprise of my comments of November 2018, after the first crash:

    "Let's make some major changes in automation, allow the aircraft to override pilot control during critical maneuvers, and let's not tell anyone about all of this. Pilots don't need to know about this stuff- we know a lot more about this airplane than they ever will, and besides, these changes are designed to compensate for poor piloting anyway and our computers are better than a lot of pilots."

    Total hubris. Total negligence. Terminal stupidity.
  • edited April 2019
    A massive current article in the Washington Post is providing many new details of the 737-MAX situation. Following are selected excerpts from that article. Unlike my previous posts here, I have not attempted to edit these excerpts for brevity because the structure of the Washington Post article is integral to proper presentation of the details being reported. I highly recommend reading the original Washington Post reportage.

    Part 1:

    While authorities in Ethi­o­pia on Thursday described key similarities between the crash of a 737 Max in Addis Ababa and another in Indonesia, important questions about their causes remain unanswered, underscoring how difficult it will be for Boeing to rebuild trust and convince newly emboldened international aviation safety regulators to allow the plane back in the air.

    In both crashes, investigators say an automated anti-stalling feature known as the Maneuvering Characteristics Augmentation System, or MCAS, repeatedly pushed the planes’ noses downward, thwarting pilots who were struggling to regain control.

    Transport Minister Dagmawit Moges said Thursday that the crew of Ethio­pian Airlines Flight 302 “performed all the procedures, repeatedly, provided by the manufacturer but was not able to control the aircraft.” She cited “repetitive uncommanded aircraft nose-down conditions,” and called on Boeing to review “flight controllability” issues on the plane.

    According to the preliminary crash report released Thursday by Ethio­pian authorities, the plane’s two external “angle-of-attack” sensors gave dramatically different readings — 74.5 degrees on the left, and 15.3 degrees on the right. The sensors are supposed to measure the difference between the nose’s direction and the angle of the oncoming wind, key information to prevent stalling. But instead, one was going haywire.

    At one point, both pilots called out “left alpha vane,” according to the cockpit voice recorder, using another name for the sensor.

    But the crew was unable to regain control of the plane and save the flight. Even after disengaging the plane’s auto­pilot, the flight data recorder shows the nose of the plane was forced down “four times without pilot’s input,” according to the preliminary report.

    Among the core questions following Moges’ statement and the release of the preliminary report is how Ethio­pian authorities on the one hand, and Boeing executives and the Federal Aviation Administration on the other, could have presented such starkly different pictures of how pilots can handle such issues with the 737 Max.

    Mike Sinnett, Boeing’s vice president of product strategy and development, said last week that “pilots can always electrically or manually override the automatic system.”

    The FAA, in an emergency order nine days after the Indonesia crash, said bad data from an external “angle-of-attack” sensor could lead to “difficulty controlling the airplane” and “possible impact with terrain.” But the FAA said pilots could “disengage autopilot” and use other controls and adjust other switches to fly the plane in such a case.

    Moges is essentially saying those procedures didn’t work. But why?

    Aviation experts also pointed to a host of additional ongoing questions about what led to the dual disasters that killed 346 people in less than five months.

    Among them: What was the precise sequence of failures — technological and human — that were at play?

    Experts said erroneous information from the “angle-of-attack” sensors triggered the automated MCAS feature that investigators believe was a factor in the disasters.

    But how did such crucial data become flawed in the first place, given that Boeing says it has tens of millions of hours of previous experience with the sensors, which it considers highly reliable?

    Amdeye Ayalew, who is heading the Ethio­pian investigation, said the sensor was neither damaged by a foreign object nor affected by a “structural design problem.”

    The Ethiopian preliminary report did, however, indicate that concerns were raised in the cockpit about an icing warning in connection with the sensor.

    “The First Officer called out Master Caution Anti-Ice,” according to the black box recording. Four seconds later, a “heat parameter” for the left angle-of-attack sensor “changed state,” according to the report. Minutes later, the First officer again mentioned the anti-ice issue, seconds before referencing the left sensor.

    And there has been no information released publicly about any ongoing mechanical problems with the Ethio­pian Airlines plane, experts said.

    “Lion Air had mechanical problems for days before the accident. Ethiopian did not. So there’s two completely different paths to get the erroneous data started,” said John Cox, a former pilot and an airline-safety consultant who has been privately briefed on the evidence in Ethi­o­pia by people familiar with the investigation. “Once the data became erroneous, then you have very similar accidents. But you have very different accidents up to there.”

  • edited April 2019
    Washington Post Article, Part 2:

    A spokesman for the FAA declined to say what the agency has learned about the source of the erroneous data in the crashes. “We continue to support the NTSB on both ongoing investigations,” the spokesman said, referring to the National Transportation Safety Board, adding the that FAA is prohibited from providing more information.

    Shem Malmquist, a Boeing 777 captain and a visiting professor at the Florida Institute of Technology, said a possible explanation for the bad data may be a malfunction in a device that filters critical flight data from the angle of attack sensors and other inputs and sends it to the pilots’ cockpit displays. Those devices are known as air data inertial reference units.

    Similar problems on Boeing, Airbus and other planes were “triggered by a bad processing algorithm, or even just a momentary data spike,” he said.

    He thinks a problem with the sensor itself is less likely.

    “I know of only a couple of events directly related to the angle of attack vanes themselves. One of those involved frozen vanes due to water getting into them during some unusual circumstances,” Malmquist said.

    Boeing has previously said it does not plan to make changes in the angle-of attack sensors it uses on several models of its planes, the 737 MAX among them.

    Instead, Boeing last week detailed a software update, in the works for months, that will change the way the data from the sensors is processed. Once the fixes are made, the MCAS feature will use data from both sensors, rather than just one — and if there’s a disagreement of more than a certain amount between the two, that automated feature won’t be used for the remainder of the flight.

    Boeing said the software fixes will also include new limits on how often MCAS activates and how strongly it seeks to correct the plane’s flight path once it does. The feature was supposed to increase safety by preventing stalling, since the 737 MAX’s designers had shifted the position of the plane’s engines as part of an effort to save fuel and compete with Airbus.

    But in a sign of the technological complexity of the fixes; potential new insights from ongoing investigations; and the realities of dealing with a regulators around the world, who led the United States in the decision to ground the planes, Boeing has now delayed sending its package of fixes to the FAA for certification. The company now says it will do so “in the coming weeks.”

    Civil aviation authorities around the world were among the first to ground the planes, and analysts said they will play a bigger role than before in decisions about returning them to the skies. Some say the FAA’s decision as the last of the major aviation safety authorities to ground the jets — along with its close ties to Boeing — may have cost it some credibility among its counterparts around the world.

    Some U.S. officials also said they do not want the planes to resume flying until an independent third-party analyzed the changes.

    To address those shared concerns, the FAA announced the formation of a technical review team to review the system. The team, chaired by former NTSB chairman Christopher Hart, will include representatives from the FAA, NASA and international aviation authorities. The FAA did not clarify which countries have been invited to join.

    “Now it is not just up to FAA to certify and say, ‘It’s good,’” Malmquist said. “All of these different agencies around the world are now saying, ‘No, we really need to have this validated,’ and that is going to be a very interesting problem that I don’t think we have seen before.”

    “China, the United Kingdom, Australia — all of them are going to be closely scrutinizing and needing to look at the changes and what’s being proposed, and everyone has to agree to it or you are going to have sections of the world where the airplane won’t be allowed to fly,” Malmquist said.

    Officials in Canada said they will not lift flight restrictions on the 737 MAX until they are “fully satisfied that all concerns have been addressed by the manufacturer and the U.S. Federal Aviation Administration and adequate flight crew procedures and training are in place.”

    There is additional information in the original Washington Post article, but (with apologies to the Washington Post) I'm already pushing reasonable limits on direct quotes from news sources.

    The Washington Post credits Lori Aratani, Luz Lazo, Michael Laris and Ashley Halsey III as the reporters for this article.

  • edited April 2019
    Considering the information in the final five paragraphs of the above Washington Post report, I find the headline for Ted's "The Closing Bell" to be quite ironic:

    Dow Rises 100 Points, Led By Boeing
  • And now this, from a current article in the San Francisco Chronicle:

    The pilots of Ethiopian Airlines Flight 302 performed all the procedures recommended by Boeing to save their doomed 737 Max 8 aircraft, but could not pull it out of a flight-system-induced dive, a preliminary report into the crash concluded Thursday.

    In a brief summary of the preliminary report, Ethiopian Transport Minister Dagmawit Moges told reporters that the "aircraft flight-control system" contributed to the plane's difficulty in gaining altitude from Addis Ababa airport before crashing six minutes later and killing all 157 on board.

    She said the crew "performed all the procedures, repeatedly, provided by the manufacturer but was not able to control the aircraft." The report, which stops short of determining the cause of the crash, chronicles the chaotic last moments aboard the flight before it crashed.

    It details how a minute after takeoff one of the angle of attack sensors sent bad information to the aircraft's system, activating the stick shaker on the pilot's column - a vibration that warns the pilot of an impending stall. Reacting to the faulty data, the MCAS system kicked in to force the plane's nose down, according to the preliminary report. The MCAS activated four separate times, and each time the pilots fought unsuccessfully to regain control of the plane.

    Black-box data showed that the crew tried to use a backup manual trim system to counter the MCAS, in an attempt to raise the plane's nose. The pilot called out "pull up" three times to tell the co-pilot to raise the nose, and in the last seconds of the flight both pilots tried together to pull the nose back up, but still could not regain control of the aircraft, according to the report. The trim system is also used to stabilize a plane.

    Experts say the airplane was traveling too fast and the manual trim wheel would have been physically impossible to operate.

    "At higher speed, manual trim may not be available due (to) airload on the stabilizer," said John Cox, a former pilot and an airline-safety consultant who has been privately briefed on the evidence by people familiar with the investigation. "Not enough force can be generated manually to move the trim."

    According to data from Flightradar24, the pilots pushed the aircraft to a speed of 380 knots - roughly 437 mph - but the plane failed to climb more than 1,000 feet above ground in an area surrounded by high terrain.

    After the [first] Indonesia crash, Boeing issued a bulletin outlining how to shut down MCAS in case of malfunction, and Thursday's preliminary report seemed to indicate that the pilots followed that procedure.

    Previous evidence found at the Ethiopian crash site showed that equipment on the 737 Max's tail was positioned in a way that would push the plane's nose down. Satellite data also showed that the Ethiopian Airlines jetliner had ascended and descended multiple times after takeoff, mirroring the behavior of the plane in the Lion Air flight.

    Both flights struggled to gain altitude, and both appeared to have erratic flight paths before crashing.

    Amid reports that a foreign object might have damaged one of the Ethiopian plane's sensors on takeoff, Amdeye Ayalew, the head of the investigation, said information from the recovered data recorders gave no such indication.

    "We did not find any information regarding the foreign object damage on the aircraft," he said. "Is there a structural design problem? No, we cannot verify that now."

    Those familiar with the investigation also point to some differences between the two flights. For example, the Ethiopian aircraft had no mechanical problems before the crash.

    The above selected excerpts from the San Francisco Chronicle article have been edited for brevity, and redundant information which has been repeatedly documented in this thread has been excluded.

    The Chronicle article credits Paul Schemm and Luz Lazo of The Washington Post as the source for their report.
  • @MFO Members: It's not ironic, Boeing has and will continue to be the world leader in commercial, defense, and areospace industry. BA is a blue chip stock that belongs in a long-term investors portfolio !
    Boeing Products:
  • ironic: happening in the opposite way to what is expected.
    • paradoxical, incongruous
  • RTFM? Remote Trifled Finnicky Mothers? Rear Term Fruit Monitor? Rat Trap Flinging Motor? Real-Time Frightening Monkey? Reginald Triangle Florida Mute?
  • Read the F___ing Manual !

    (As all engineers and technicians have said at some point in their lives.)
  • Well @Old_Joe, Art Cashin agrees with you. It is ironic the stock went up. (I enjoy his daily narratives).
  • edited April 2019
    Angle-of-Attack Vanes



    The "vane" itself is a small wing-like airflow surface. Airflow passing this vane causes it to deflect and rotate in one direction or the other. Internal sensors detect and measure this deflection, which then becomes a raw data input to the plane's computing equipment.
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