Boeing 737 Max
POSTED BY: SIGNYM
UPDATED: Friday, August 21, 2026 17:40
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There is no clear consensus on when the Boeing 737 MAX will fly again. However, some airlines are banking on using the aircraft from July. Air Canada has currently removed the aircraft from its schedules until 1st July, while TUI has arranged cover for the aircraft until mid-July. There is considerable uncertainty around when the 737 Max will return to service.
https://simpleflying.com/boeing-737-max-flying-again/
The Joss Whedon script for Serenity, where Wash lives, is Serenity-190pages.pdf at www.mediafire.com/folder/1uwh75oa407q8/Firefly
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The 737 Max’s instability problems eerily echoed another ’60s design, the Cheyenne. At the time, Piper Aircraft wanted to build a more powerful version of its popular twin-engine light aircraft, the Navajo. Piper swapped out its piston engines for turboprops. Like the 737 Max, the Cheyenne had a design that involved putting more powerful engines further forward on the wing.
Jack Webb was Piper’s chief engineering test pilot during most of the Cheyenne development process. “As we were going along, I discovered a kind of scary dynamic-stability problem,” he says. It was the same problem the 737 Max would later have, for the same reason. And as Boeing would later do, Piper tried to fix the problem by adding automation — in its case, a device called a “stability-augmentation system” (SAS) that would push the nose down if it got too high.
Webb came to realize that if the pilot wasn’t properly trained, the SAS could actually worsen the instability. The problem was that the system could get into a feedback loop with the human pilot. Not understanding why the nose was starting to go down, the pilot would pull up, to which the SAS would respond by pushing down. Since each has a lag in their response time, they wind up chasing one another, causing the plane to enter a series of increasingly steep climbs and dives.
Webb believes that this kind of up-and-down motion can take place even when the system is functioning as designed. He has looked at several accidents involving the Cheyenne, “and it’s a classic picture. It looks like the airplane’s on a roller-coaster ride before it crashes. The pilots just get behind the input necessary to stabilize the airplane. They’re fighting it.”
Webb believes that, based on his experience with the Cheyenne, these fixes won’t eliminate the Max’s predilection for roller-coastering. Even if Webb is wrong, and the 737 Max is safe so long as its MCAS is working as intended, that still leaves another problem. A single malfunctioning sensor will cause the system to turn off, thus putting the plane back in the condition that the FAA deemed too unstable to grant an airworthiness certificate.
There is a straightforward solution for all the 737 Max’s problems: to reduce the plane’s pitch up tendency, Boeing could lengthen the landing gear and move the engines further back under the wing; and to increase stability, it could increase the size of the tail. There’s a reason that Boeing won’t do that: All existing 737 Maxs would go to the junkyard.
http://nymag.com/intelligencer/2019/03/is-the-boeing-737-max-worth-sav
ing.html
The Joss Whedon script for Serenity, where Wash lives, is Serenity-190pages.pdf at www.mediafire.com/folder/1uwh75oa407q8/Firefly
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There was a prominent no-show among the 200 regulators, pilots and airline managers that Boeing Co. invited to preview a crucial software update for the 737 Max this week, said people familiar with the matter: the European Union Aviation Safety Agency (EASA).
EASA’s snub points to the delicate politics Boeing faces in convincing regulators the Max is safe as the company seeks to restore confidence in its bestselling jet, which has been grounded for more than two weeks. The reputation of U.S. regulators has taken a hit in the scrutiny of the 737 Max's approval process, and foreign agencies are less likely to rubber-stamp aircraft certifications simply because they have been cleared by the Federal Aviation Administration.
EASA is expected to play an influential role in determining how long and complicated the review of the Max will be, while safety officials from China to Canada have vowed to conduct their own rigorous analysis.
More at www.latimes.com/business/la-fi-737-max-boeing-eu-20190331-story.html
The Joss Whedon script for Serenity, where Wash lives, is Serenity-190pages.pdf at www.mediafire.com/folder/1uwh75oa407q8/Firefly
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Boeing executives are offering a simple explanation for why the company’s best-selling plane in the world, the 737 Max 8, crashed twice in the past several months. Executives claimed on March 27 that the cause was a software problem — and that a new software upgrade fixes it.
But this open-and-shut version of events conflicts with what diligent reporters in the aviation press have uncovered in the weeks since Asia, Europe, Canada, and then the United States grounded the planes.
The specifics of what happened in the regulatory system are still emerging. But the big picture is coming into view: A major employer faced a major financial threat, and short-term politics and greed won out over the integrity of the regulatory system. It’s a scandal.
More at www.vox.com/business-and-finance/2019/3/29/18281270/737-max-faa-scanda
l-explained
The Joss Whedon script for Serenity, where Wash lives, is Serenity-190pages.pdf at www.mediafire.com/folder/1uwh75oa407q8/Firefly
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According to WJS [via ZH], the pilots of the Ethiopian jet DID turn off the electric motors and attempt manual control, but apparently felt that procedure wasn't working (or maybe wasn't working fast enough) so the turned the electric motors back on which re-engaged the MACS and sent the plane into its final nose dive.
Quote:
The pilots on Ethiopian Airlines Flight 302 initially reacted to the emergency by shutting off power to electric motors driven by the automated system, these people said, but then appear to have re-engaged the system to cope with a persistent steep nose-down angle. It wasn’t immediately clear why the pilots turned the automated system back on instead of continuing to follow Boeing’s standard emergency checklist, but government and industry officials said the likely reason would have been because manual controls to raise the nose didn’t achieve the desired results.
After first cranking a manual wheel in the cockpit that controls the same movable surfaces on the plane’s tail that MCAS had affected, the pilots turned electric power back on, one of these people said. They began to use electric switches to try to raise the plane’s nose, according to these people. But the electric power also reactivated MCAS, allowing it to continue its strong downward commands, the people said.
Reuters, which was also the recipient of leaks from investigators, offered a slightly different version of events. It reported that MCAS was reengaged four times as pilots scrambled to right the plane, and that investigators were looking into the possibility that the software might have reengaged without prompting from the pilots.
https://www.zerohedge.com/news/2019-04-03/bad-news-boeing-preliminary-
report-shows-anti-stall-software-sealed-flight-et302s
Of course, these are leaked fragments of a preliminary report, obviously being interpreted differently by different media outlets. Even with a full report we may not know exacly what happened ... IIRC the cockpit voice recorder was damaged beyond retrievability by the high speed of the crash.
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Quote:
Originally posted by SIGNYM:
According to WJS [via ZH], the pilots of the Ethiopian jet DID turn off the electric motors and attempt manual control, but apparently felt that procedure wasn't working (or maybe wasn't working fast enough) so the turned the electric motors back on which re-engaged the MACS and sent the plane into its final nose dive.Quote:
The pilots on Ethiopian Airlines Flight 302 initially reacted to the emergency by shutting off power to electric motors driven by the automated system, these people said, but then appear to have re-engaged the system to cope with a persistent steep nose-down angle. It wasn’t immediately clear why the pilots turned the automated system back on instead of continuing to follow Boeing’s standard emergency checklist, but government and industry officials said the likely reason would have been because manual controls to raise the nose didn’t achieve the desired results.
After first cranking a manual wheel in the cockpit that controls the same movable surfaces on the plane’s tail that MCAS had affected, the pilots turned electric power back on, one of these people said. They began to use electric switches to try to raise the plane’s nose, according to these people. But the electric power also reactivated MCAS, allowing it to continue its strong downward commands, the people said.
Reuters, which was also the recipient of leaks from investigators, offered a slightly different version of events. It reported that MCAS was reengaged four times as pilots scrambled to right the plane, and that investigators were looking into the possibility that the software might have reengaged without prompting from the pilots.
https://www.zerohedge.com/news/2019-04-03/bad-news-boeing-preliminary-
report-shows-anti-stall-software-sealed-flight-et302s
Of course, these are leaked fragments of a preliminary report, obviously being interpreted differently by different media outlets. Even with a full report we may not know exacly what happened ... IIRC the cockpit voice recorder was damaged beyond retrievability by the high speed of the crash.
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A little bit more of the same:
https://ca.finance.yahoo.com/news/boeing-737-max-defense-just-10235028
7.html
(Bloomberg Opinion) -- In the wake of the October crash involving a Lion Air Boeing 737 Max jet in Indonesia, Boeing Co. sent out a bulletin reminding pilots how to counteract an un-commanded descent.
The implication was that even if the passenger jet’s so-called MCAS anti-stall software malfunctions due to erroneous data and pushes the nose down, the crew should still be able to save the plane — as happened on an earlier Lion Air flight.
“The 737 Max is as safe as any airplane that has ever flown the skies,” Boeing swiftly concluded.
Lion Air was furious that the manufacturer appeared to be casting doubt on its safety culture, but for everyone else it sent a comforting message: Perhaps Boeing was right about the 737 Max.
So when a second 737 Max aircraft crashed last month in similar circumstances in Ethiopia, there was puzzlement: Surely the pilot must have known about MCAS and how to switch it off. So why hadn’t he?
On Wednesday, the Wall Street Journal provided an initial answer to that question, and it’s not a reassuring one for Boeing, its investors and customers.
The Ethiopian Airlines pilot did manage to disable MCAS, at least temporarily, but was still unable to get the aircraft to climb again, the newspaper reported, citing people familiar with the crash investigation’s preliminary findings.
If that is correct, then Boeing and the U.S. regulators may have provided insufficient advice to pilots in their initial bulletin and were too hasty in pronouncing the aircraft safe. It would also increase the likelihood the manufacturer could be sued for damages. Before the Journal report, Bloomberg Intelligence put those costs at an estimated $1 billion.
The report could also sow doubt about whether the software and sensor fixes that Boeing is proposing are sufficient and thus prolong the period that the 737 Max will remain grounded. Customers like TUI AG are already preparing for the possibility they may not be able to fly the jet again for several months.
To be clear, there are other details in the Journal’s report that require further clarification. We don’t know why the crew couldn’t get the aircraft to climb. The MCAS eventually reactivated again, which forced the nose down even more. Again, it’s not clear why this happened. The Journal says the pilots switched it on, but a separate Reuters report says this may not have been intentional.
Ethiopia’s regulator is expected to release its initial report on the crash in coming days. Its counterparts in Canada, China, Europe and elsewhere were already expected scrutinize the findings, and Boeing’s proposed fixes, extremely carefully. Together with the families of the 346 crash victims, they will now be watching like hawks.
To contact the author of this story: Chris Bryant at cbryant32@bloomberg.net
To contact the editor responsible for this story: Edward Evans at eevans3@bloomberg.net
This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.
Chris Bryant is a Bloomberg Opinion columnist covering industrial companies. He previously worked for the Financial Times.
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The Ethiopian accident report (April 4th) adds to concerns about the model, because pilots were aware of the anti-stall system and appear to have done what they were supposed to if it activated erroneously—two major differences from the Lion Air crash in Indonesia that killed 189 people last October.
Responding to queries from reporters regarding the design and inherent safety of the plane, Amdeye Fenta, chief of the Ethiopian Accident Information Bureau, added, “Is there a structural design problem? We cannot predict right now.”
Reports have questioned if the two pilots on the doomed Ethiopian flight were trained on the simulator. The carrier, without confirming if they did, has said the B-737 MAX full flight simulators were not designed to simulate the MCAS situation faced by Lion Air.
https://qz.com/africa/1587323/
The Joss Whedon script for Serenity, where Wash lives, is Serenity-190pages.pdf at www.mediafire.com/folder/1uwh75oa407q8/Firefly
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Yesterday, Boeing confirmed to The Washington Post that it had found a second software problem that the Federal Aviation Administration has ordered fixed - separate from the anti-stall system under investigation in the two crashes, and that had led to the aircraft's worldwide grounding.
That additional problem pertains to software affecting flaps and other flight stabilization hardware and is therefore classified as critical to flight safety, said two officials who spoke on condition of anonymity to discuss the ongoing probe.
The realization of a second software problem explains why the timeline that Boeing projected publicly last week for getting hundreds of the aircraft airborne again has slipped, the officials said.
Boeing initially said it planned to submit fixes for its stall-prevention system to the FAA for review last week. On Monday, an FAA spokesman said the agency instead expected to receive the final package of software "over the coming weeks."
"Obviously, we ended up at a situation that in hindsight was not supposed to happen," one of the officials familiar with the investigation told The Washington Post. "Now, you don't want to be in a situation where there was one contributing factor to an accident, and then three weeks later you, find another one.
www.philly.com/news/nation-world/software-problem-boeing-flight-contro
l-system-ethiopian-airlines-20190405.html
The Joss Whedon script for Serenity, where Wash lives, is Serenity-190pages.pdf at www.mediafire.com/folder/1uwh75oa407q8/Firefly
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The airline’s youngest-ever captain, a 29-year-old with an impressive 8,100 hours flying time, and his rookie 25-year-old co-pilot may have made a crucial mistake by leaving the engines at full take-off power, according to data and other pilots.
By the end, the aircraft was traveling at 500 knots (575 mph, 926 kph), far beyond its design limits. A “clacker” warning was telling the pilots their aircraft was going too fast. Data confirms the engines stayed at nearly full power. Other 737 pilots say that made the crew’s job tougher by making the controls much harder to move. . . .
That and some other potential missteps may have left them unable to fight flawed Boeing software that eventually sent the jet into an uncontrollable dive, experts said after studying the data.
“Power being left in take-off power while leveling off at that speed is not a normal procedure,” said one U.S. pilot, who declined to be named because he was not authorized to speak to the media. “I can’t imagine a scenario where you’d need to do that.” . . .
The combination of excess speed and cutting off the system while the plane was still leaning downwards meant up to 50 pounds of force would be needed to move the control column, and moving the manual trim wheels was impossible. . . . The captain asked the co-pilot to try to trim the plane manually using a wheel in the center console to lift the nose and make it easier to recover from the dive. But it was too hard to move the wheel. Both men then tried to pitch the nose up together. The captain, according to the report, said it was not enough.
www.reuters.com/article/us-ethiopia-airplane-reconstruction-insi/how-e
xcess-speed-hasty-commands-and-flawed-software-doomed-an-ethiopian-airlines-737-max-idUSKCN1RH0FJ
The Joss Whedon script for Serenity, where Wash lives, is Serenity-190pages.pdf at www.mediafire.com/folder/1uwh75oa407q8/Firefly
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