It's a combination of factors. Primarily Bad design to use a single AoA as a data source, but also lack of knowledge to use the trim cutout switches. The JT aircraft that crashed had the same issue the flight before. The pilots there were able to handle the issue.

Given the aircraft has been grounded for 2 years and is being extensively and properly vetted by the FAA, EASA etc. It should be different when it reenters service.

Total Fiction
 

Disclaimer: this is totally a figment of my imagination. Any resemblance to past events/personalities is purely coincidental and unintended...

737-MAX development saga

Number Cruncher(Guy in suit): "Lets extend the fuselage, add more seats and we have a new plane. We will still keep it 737 in name so airlines don't have to get pilots trained. They won't buy if we call it a 'new' plane"
Engineer: "Why?"
Number Cruncher: "Because then they have to send pilots for training and certification and they will ask us to absorb those costs"
Engineer: "OK. We need bigger engines for that"
Number Cruncher: (smiles) "I know, we have a bigger engine lined up"
Engineer: "Can't put it on this air-frame, not enough ground clearance"
Number Cruncher: "Well then move it higher on the wing"
Engineer: "No can do. That will change the thrust vector. Planes become unstable when you change thrust vectors"
"Try gripping a model plane - in a pinch grip just where the engines are - near the fuselage. Now move the grip outwards and also more forward on the wing. see how easily it rotates and pushes the nose up. Now you are at risk of stall"
Number Cruncher: "Ok then I will talk to the software guys to get the nose pushed down"
Engineer: (surprised) "So you will still allow the plane to be nose up and unstable in design?"
Number Cruncher: "You just put those engines on the plane. Software guys will fix this"

Engineer shakes his head....

we know how good the software solution was....

Nope. Like the DC10 after its grounding. Or even the 787. It will be will probably get extra attention and a focus on pilot training. Probably will be one of the safest planes in the sky.

Especially the Oasis-configured AA 737s!

Yes. I am confident about 737-MAX flights. Hopefully everything is smooth. They won't have anymore problems.

Congressional report out today:
https://www.usatoday.com/story/trave...es/5809550002/"The committee's report dwells on how, at multiple points in the development of the Max, engineers and test pilots noted problems in MCAS that would later prove to be at the root of the crashes.

As early as 2012, a Boeing test pilot found it took 10 seconds to deal with an uncommanded activation of the MCAS system, which was deemed to be "catastrophic," the report discloses."

A test pilot noted that the MCAS system could kick in multiple times, leaving the plane's ability to stay aloft badly hindered, which is what sealed the fate of the Lion Air and Ethiopian flights, according to the report.

The 737 Max's chief engineer said he approved MCAS without really understanding it, the report states, a reflection of a management system in which he had overall authority, but most of the engineers on the project reported directly to others.

Well, that's certainly eye-opening, though at this point not really surprising.

A movie should be made about Boeing's internal chaos...

It can be a sequel to this.

Captain Chesley “Sully” Sullenberger of US Airways fame and recognized aviation flight safety expert weighed in with his expert opinions on the future of the 737 MAX in the Seattle Times on October 9. In part: (link)“...even if the FAA ungrounds the jet next month as expected, additional modifications are needed as soon as possible to improve the plane’s crew alerting system and add a third check on the jet’s angle of attack data.

‘I’m not going to say, ‘We’re done, good enough, move on,' said Sullenberger.

‘People are going to fly on it and I will probably be one of them,’ he added. ‘The updated MAX will probably be as safe as the (previous model) 737 NG when they are done with it. But it’s not as good as it should be.’...

Dennis Tajer, spokesman for the Allied Pilots Association (APA), the union representing American Airlines pilots, said he’s with Sullenberger.“

“In June 2019, testifying at a 737 MAX investigation hearing before the U.S. House Transportation Committee, he severely criticized both Boeing’s design failures and the FAA’s oversight during certification of the MAX.

With the ungrounding of the MAX now imminent, he weighed in on what still needs to be done.

His first concern echoes that of the European Aviation Safety Agency (EASA) and many of the public comments submitted on the FAA proposal: MCAS on the updated MAX will take input from the jet’s two angle-of-attack sensors, but Sullenberger believes a third check is necessary.

If one of two sensors is faulty, the computers won’t know which is correct.

The likely solution is not a third angle of attack vane on the jet’s exterior, but an indirect, “synthetic” software calculation of the angle of attack based on parameters such as the aircraft’s weight, speed, inertial position and GPS signal.

Boeing’s newest jet, the 787, has such a check on the reliability of its air data sensors called Synthetic Airspeed, a system Boeing rejected for the MAX on cost grounds.”

As a onetime frequent flyer and former pilot, and one who lived through the Comet, Electra and DC-10 debacles, I certainly agree with Captain Sully. But at least pilots will be warned when their is angle of attack disagreement and with the proper training take corrective action, even if Boeing tries to evade doing what I consider the right thing. (If Boeing wants to recover it’s reputation...)

I don’t remember what happened DC10 crashes. Did they grounded all DC10? For how long?

Okay. I just found out. The DC-10 is grounded for 37 days. Due to 3 aircraft was crashes.

Here’s a link:

https://simpleflying.com/dc-10-1979-grounding/

Yes, just a little over a month. The primary reason for the grounding was AA191, though Douglas was able to make the necessary modifications to get the aircraft airworthy again pretty quickly. At least, relative to this.

The other piece of the puzzle is at the time, the DC-10 was a much more essential aircraft than the 737MAX is now. It was the backbone of many airlines' long-haul fleets and not easily replaced.

FAA Updates on Boeing 737 MAX 18 Nov 2020
 

FAA Updates on Boeing 737 MAX

11/18/2020

FAA Statement on Boeing 737 Max Return to Service - link

FAA Administrator Steve Dickson today signed an order (PDF) that paves the way for the Boeing 737 MAX to return to commercial service. Administrator Dickson’s action followed a comprehensive and methodical safety review process (PDF) that took 20 months to complete. During that time, FAA employees worked diligently to identify and address the safety issues that played a role in the tragic loss of 346 lives aboard Lion Air Flight 610 and Ethiopian Airlines Flight 302. Throughout our transparent process, we cooperated closely with our foreign counterparts on every aspect of the return to service. Additionally, Administrator Dickson personally took the recommended pilot training and piloted the Boeing 737 MAX, so he could experience the handling of the aircraft firsthand.

In addition to rescinding the order that grounded the aircraft, the FAA today published an Airworthiness Directive (PDF) specifying design changes that must be made before the aircraft returns to service, issued a Continued Airworthiness Notification to the International Community (CANIC) (PDF), and published the MAX training requirements. (PDF) These actions do not allow the MAX to return immediately to the skies. The FAA must approve 737 MAX pilot training program revisions for each U.S. airline operating the MAX and will retain its authority to issue airworthiness certificates and export certificates of airworthiness for all new 737 MAX aircraft manufactured since the FAA issued the grounding order. Furthermore, airlines that have parked their MAX aircraft must take required maintenance steps to prepare them to fly again. (Emphasis added.)

The design and certification of this aircraft included an unprecedented level of collaborative and independent reviews by aviation authorities around the world. Those regulators have indicated that Boeing’s design changes, together with the changes to crew procedures and training enhancements, will give them the confidence to validate the aircraft as safe to fly in their respective countries and regions. Following the return to service, the FAA will continue to work closely with our foreign civil aviation partners to evaluate any potential additional enhancements for the aircraft. The agency also will conduct the same rigorous, continued operational safety oversight of the MAX that we provide for the entire U.S. commercial fleet.

View a video from Administrator Dickson.

View all documents related to the Airworthiness Directive and return to service https://www.faa.gov/foia/electronic_..._reading_room/

For some reason, the FAA's representation that "the design and certification of this aircraft included an unprecedented level of collaborative and independent reviews by aviation authorities around the world" does not provide an unwavering level of reassurance.

Boeing’s Maneuvering Characteristics Augmentation System, known as MCAS, will now rely on readings from two Angle of Attack (AoA) sensors that measure the angle at which the wing slices through the air, instead of just one.

MCAS will activate only if both sensors are in agreement, and it will activate only one time, Boeing has said. Separately, Boeing is making standard an alarm alerting pilots to a mismatch of flight data from the sensors.

Pilots must undergo new simulator training, including training on multiple flight-deck alerts during unusual conditions, along with how to respond to a situation known as runaway stabilizer with timely pilot actions required. Pilots must also get training for erroneous, high Angle of Attack malfunctions.

American Airlines expects to train some 1,700 of its 4,000 737 pilots in December with a one hour and 40 minute iPad course and a two-hour simulator session that will follow a one-hour briefing, the union representing its pilots said.

https://in.reuters.com/article/boein...KBN27Y2DJ?il=0

Thanks for that information. Please correct me if I am wrong, but with the two loss of 737 MAX 8 aircraft, those planes were equipped with only one angle of attack sensor (which failed). I believe the U.S. carriers, including American, chose to go with the redundancy of the two sensors. It sounds like the original MCAS programming may not have even handled the failure of one sensor (but not both) correctly, or did that redundancy make it less likely for an unwanted MCAS activation?

Here is the latest 737 Max incident. An Air Canada bird was being returned from the desert when shortly after takeoff, they had a fuel imbalance in the left wing, leading to engine shutduwn and an abort back to Tucson.

https://www.zerohedge.com/markets/ai...ergency-flight

Fortunately no pax aboard.

Much ado about nothing.

Doesn't seem like a type-specific incident, but any problem on a 737 Max is going to be bad press.

not type specific, but anytime planes sit for long periods of time, they are more likely to have an issue, even if they get inspected prior to flight

Id think any aircraft sitting out on tarmac somewhere in mothballs, as carefully as they prepare them, have a higher risk of something like this going wrong as they’re on test flights or flying to return to duty.

All MAX aircraft had and have two angle of attack vanes / sensors. AA was the only airline I the USA that opted for the angle of attack indicators included in the primary flight display, and a comparator circuit with disagree warnings for out of synch AOA signals (see illustration)

. The other two airlines, iirc, WN ordered one option, but Boeing failed to inform them the warning would not work if you didn’t buy the flight display indication, and UA didn’t order either option. The two airlines that suffered the MAX losses also opted to save money by not purchasing what Boeing at the time offered as mere options at extra cost.


https://cimg0.ibsrv.net/gimg/www.fly...0aa75d6bd.jpeg


Of course both AOA indication and AOA disagree warning are now required for safer operation of all MAX aircraft, at no cost, along with updated MCAS, operating manuals, pilot training and some other details including a wiring issue.

The link in the quoted post is to a blog best known for its sensationalist headlines.