The software documentations system, IT, blew up. Understanding that is another cause investigation.

I don't think you understand what software documentation is. It's actually only a description and also some transliteration of the code. That documentation is written after the code has been written and tested which means the interpretation of the code not always is the same and rather useless since you cannot test it. Hopefully the code does what the specification tell and that is more important.
In this case it looks to me more like the specification is not complete...
"Oh. Do we have two sensors... Oh. There is a pilot trying to turn off the MCAS... Oh. The pilot need a motor to trim the stabilizer..." and so on...

In this case it would appear it is not the "fault" of software documentation, but the "fault" of the system concept, or maybe the system modification during development. Decisions were made that led to the software doing what it was intended to do, but that was wrong [mode = hindsight 20/20] - the system was (re)designed as a none-redundant one, with no limits on its actions. Coupe that with a pair of switches that turned the power off to the tail stabiliser trim jack and one has a system failure not a software (documentation) failure.
If it is true that there was a change in use of the AoA sensors from "redundant" to "non-redundant" then the failure lies fair and square within the remit of the design authority (Boeing) and not the component manufacturer. And the same is true even if it was a "day-zero" design decision.

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

It has been known for a long time that AoA sensors fail, and can fail in what might be considered "wrong side" modes - I can think of three (max-up, max-down, false centre) and no doubt there a fair number of others, and probably just as many causes.
Boeing fitted two of them for a reason, but decided to use only one of them during each climb-out. With two fitted there is a fair chance that a system will detect that there is an imbalance between them, and, because there are only two (Airbus and others use three or more) there can't be a vote to see which one is wrong, you have to isolate the system, and do so in a manner that enables the crew to fly "normally" - clearly tell them the system (MCAS) is cut out, and that they will have to fly the plane themselves, not relying on the system to stop them exceeding flight limitations.
Remember MCAS was (initially) described as an augmentation system, not a safety system. But as has been uncovered it has an ability to cause an unsafe flight status. The "intent" of MCAS was "Manoeuvring Characteristic Augmentation System" - not an anti-stall system, but one to allow the pilot to fly the plane in a sufficiently similar manner to the earlier versions.

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

the system was (re)designed as a none-redundant one, with no limits on its actions. Coupe that with a pair of switches that turned the power off to the tail stabiliser trim jack and one has a system failure not a software (documentation) failure.
If it is true that there was a change in use of the AoA sensors from "redundant" to "non-redundant" then the failure lies fair and square within the remit of the design authority (Boeing) and not the component manufacturer..

That is the reason why 2 aircraft crashed with the loss of 346 lives. A flaw that Boeing engineers found in 2017. Boeing then instigated a Safety Review Board which came to the conclusion that it was not a safety issue & passed the results to the FAA who concurred.
1: Who were the members on that SRB?
2: Did the FAA blindly accept those results?
3: Aircraft have redundant systems in place to cover failures. Where was the redundant system for the trim stabilisers?
With regards to No 3, I cannot stop thinking of flight 1549 - activation of the APU is 15th on the checklist. Sully activated it early, an activation that saved all lives on-board that aircraft. Manual operation of the trim stabilisers is NOT a backup imho.

@Gary, the statement that all components have to be tested for airworthiness is ridiculous. All components are manufactured to a specification, tested to ensure they work & fit for purpose. Your fixation on the AoA failure & software documentation is also senseless. Rob has clearly highlighted the major cause of the crashes in the quote above.

There's two very good clear summaries from Prof Simon that covers the points we're flying through on this thread:


Workshop model of 737 Max 8 systems - Prof Simon

Trying hard to understand what happened to the Boeing 737 max 8 aircraft, I build a model in my workshop to explain the MCAS system, elevator Trim and cockpit. It helped ME understand how things work. Obviously it's made of bits laying around and I am neither an engineer or a commercial pilot, so go easy on my attempts to make things a little clearer. My CFI [Chief Flying Instructor] said, washing an aircraft or building a model will help you get to know them. Good advice...


Note also for the Ethiopian catastrophe, the pilots were flying at the upper end of the capabilities of the aircraft due to being at take-off, with their full fuel load for the flight, from an airport in the mountains with hot weather. Note also that aircraft can be left grounded when the air temperature becomes too hot for takeoff (due to the lower air density reducing the available lift).

Note that for the Lion Air crash, the pilots there were flying at night and were left troubleshooting what was wrong, including whether their instruments might have been at fault! All whilst still, moment by moment, desperately flying the aircraft to stay airborne.


How MCAS was born on the 737 max 8 - Prof Simon

I had always wondered how MCAS was born. The 737 max 8 aircraft must have been built without a software handling patch. It is a fascinating and potentially deadly story. Prof Simon relates the tale. Original research by the New York Times.



For my following of this disastrous story, we should never have got as far as the Lion Air disaster. To then continue onto the Ethiopia disaster is nothing short of a catastrophe.

All in our only one world,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

For my following of this disastrous story, we should never have got as far as the Lion Air disaster. To then continue onto the Ethiopia disaster is nothing short of a catastrophe.

Boeing discussed the status of the AOA Disagree alert with the FAA in the wake of the Lion Air accident. At that time, Boeing informed the FAA that Boeing engineers had identified the software issue in 2017 and had determined per Boeing’s standard process that the issue did not adversely impact airplane safety or operation. In December 2018, Boeing convened a Safety Review Board (SRB) to consider again whether the absence of the AOA Disagree alert from certain 737 MAX flight displays presented a safety issue. That SRB confirmed Boeing’s prior conclusion that it did not. Boeing shared this conclusion and the supporting SRB analysis with the FAA.

Agreed.

All components are manufactured to a specification, tested to ensure they work & fit for purpose.

Well, not always.
FAA issued this update on Boeing 737 MAX yesterday. Not about the MCAS but anyway...
https://www.faa.gov/news/updates/?newsId=93206

Boeing suffered similar problems in the early days of the 737's production.
Their current answer to that is:

At the same time, Boeing said it was eliminating about a hundred quality control positions in North Charleston.

All components are manufactured to a specification, tested to ensure they work & fit for purpose.

Well, not always.
FAA issued this update on Boeing 737 MAX yesterday. Not about the MCAS but anyway...
https://www.faa.gov/news/updates/?newsId=93206

Thanks for that, that's a good source for a lot more of the detail for recent 'events'...


And that latest snippet has hit the main media:

Boeing informs FAA about improperly manufactured parts on some passenger planes

... Boeing has informed them that some parts for the company's grounded 737 Max passenger plane, and prior model 737 Next Generation (NG), may have been improperly manufactured. Boeing said the part known as a leading-edge slat track — a mechanism that modifies the lift and drag characteristics of the plane's wing during takeoffs and landings — is among 148 parts from a Boeing supplier that are under concern.

According to the FAA, 32 Boeing NG and 33 Boeing Max aircraft are affected in the U.S., with the number increasing to 133 NG and 179 Max worldwide.

In its statement, the FAA said, "The affected parts may be susceptible to premature failure or cracks resulting from the improper manufacturing process. Although a complete failure of a leading-edge slat track would not result in the loss of the aircraft, a risk remains that a failed part could lead to aircraft damage in flight."...

... On Wednesday, Boeing CEO Dennis Muilenburg told "CBS Evening News" incoming anchor Norah O'Donnell, "We can't change what has happened in these accidents but we can be absolutely resolute in what we're going to do on safety going forward."


Boeing says some of its 737 Max planes may have defective parts

... The company discovered the problem Friday, when Boeing was meeting with the parts supplier. Boeing employees noticed some of the parts were not heat treated, which led them to believe there might be a safety issue...


Boeing Says Some 737 Max Planes Might Have Defective Parts - China Airlines Flight 120 example

... "When the aircraft retracted the slats after landing at Naha Airport, the track can that housed the inboard main track of the No. 5 slat on the right wing was punctured, creating a hole. Fuel leaked out through the hole, reaching the outside of the wing. A fire started when the leaked fuel came into contact with high-temperature areas on the right engine after the aircraft stopped in its assigned spot, and the aircraft burned out after several explosions."...



In my most humble uneducated opinion:

So... The non heat-treatment that is usually used to make parts stronger and/or more durable is a case of deliberate cost-cutting or a stupid mistake. All with the expectation that noone will notice?

That looks to be the case in that Boeing indeed didn't notice and planes are flying in the air with flying parts that can be expected to prematurely fail with a possible following disaster where people are killed.

Looks like the present certification system is not working as it should... Due to cutting costs to boost greedy profits?


All in our only one world,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

... And that latest snippet has hit the main media:

Boeing informs FAA about improperly manufactured parts on some passenger planes

... Boeing has informed them that some parts for the company's grounded 737 Max passenger plane, and prior model 737 Next Generation (NG), may have been improperly manufactured. Boeing said the part known as a leading-edge slat track — a mechanism that modifies the lift and drag characteristics of the plane's wing during takeoffs and landings — is among 148 parts from a Boeing supplier that are under concern.

According to the FAA, 32 Boeing NG and 33 Boeing Max aircraft are affected in the U.S., with the number increasing to 133 NG and 179 Max worldwide.

In its statement, the FAA said, "The affected parts may be susceptible to premature failure or cracks resulting from the improper manufacturing process. Although a complete failure of a leading-edge slat track would not result in the loss of the aircraft, a risk remains that a failed part could lead to aircraft damage in flight."...

... On Wednesday, Boeing CEO Dennis Muilenburg told "CBS Evening News" incoming anchor Norah O'Donnell, "We can't change what has happened in these accidents but we can be absolutely resolute in what we're going to do on safety going forward."

Really... Despite the same commercial-with-no-morals pressure for profit with all greed? Really?... Does a leopard voluntarily change all its spots?...

Those people in charge/command, and particularly their mentality and ways of doing things, were in part the cause for the downing of two planes killing all on board. In my humble opinion, those people are completely unfit for any field of work where peoples lives depend on that work...


Again, also it looks like the present certification system is not working as it should... Due to cutting costs to boost greedy profits?


All in our only one world,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

I think you'll find that is the case today within the Logistics industry as a whole.
I watched an excellent 3 parter last year - Britain's Biggest Warship about the Queen Elizabeth Aircraft Carrier.
I know that trials are there to detect & remedy any issues that crop up, but surely the builders can ensure that the main propulsion is actually fitted & secured correctly.
It wasn't. The securing bolts on one of the props were not secured enough & that caused major issues for the ship.
As we are now seeing, skilled workmanship & quality control is now in the past costing people their lives. :-(

Snip from a BBC news story today:

Boeing is working on a software fix that will allow the Max to begin flying again, but differences have arisen between the US and Canada on how to train pilots on the software after the update.
Washington believes training on computers or tablets is sufficient for seasoned pilots, but Ottawa wants to require training on flight simulators.

Given that the intent of MCAS was to make the b737Max handle the same as an older generation b737 by countering the tendency for the nose to pitch up under certain conditions it makes sense to me for pilots to have to learn how to handle this characteristic without MCAS active. And the only "safe" way of doing this will be in a simulator, and one which correctly simulates the changes in stick forces etc.

---

Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

Snip from a BBC news story today:
Boeing is working on a software fix that will allow the Max to begin flying again, but differences have arisen between the US and Canada on how to train pilots on the software after the update.
Washington believes training on computers or tablets is sufficient for seasoned pilots, but Ottawa wants to require training on flight simulators.

ROFLMAO

Boeing doesn't require pilot training in simulator between the variants of Boeing 737 to be a certified 737 pilot. Never has and I think it's the same for other companies.
A pilot only need to learn, not train, the differences between them. Learning from paper manuals or now iPads and such.
https://youtu.be/CD0JabYjF3A?t=451
With the 737MAX the problem starts. Boeing think the MCAS is enough to qualify it only a variant and not a new type of aircraft.
Pilots would then need simulator training if the 737MAX is to be considered a new type.
Boeing of course in the competition with Airbus tries to avoid that "at all cost".

Boeing of course in the competition with Airbus tries to avoid that "at all cost".

Of course, mustn't interfere with the profit margins.

Why did I think this plane had been made a bit longer? Anyway...

I don't think we should care what the pilots think really. They're not exactly risk-averse and will fly almost anything.
Engineering is a whole other department. I'm sure a real engineer would find it insulting for MCAS to exist at all.
- - - - - - - - - - -

60 Minutes Australia video has been re-uploaded. They state quite factually that this is profits before lives.

Timestampted video below is the part about their race with Airbus and why this is an engineering problem. But you can rewind and watch the whole show from the start if you wish :)

https://youtu.be/aO7_indbfME?t=435

and a similar video (with over 7 million views)
A few of the comments I've made here seem to be shared by others below the video.
https://www.youtube.com/watch?v=H2tuKiiznsY

So why did Boeing had to move 737MAX 's engines in the first place?
https://youtu.be/H2tuKiiznsY?t=111
Yes. Luggage handling is apparently expensive so the landing gear of a Boeing 737 is much shorter than an Airbus have.
Business as usual...

60 Minutes Australia video has been re-uploaded. They state quite factually that this is profits before lives.

Boeing went with MCAS & 1 AoA sensor because they knew that the FAA would demand Level D Flight Simulation training if they used 2. A deliberate decision from Boeing.
Boeing: We will re-engineer the 737 if you give us half of your Airbus order of 200.
American Airlines: Okay.
You Yanks outdo Islam in its love for Allah. with your own No 1 Love:

A few of the comments I've made here seem to be shared by others below the video.
https://www.youtube.com/watch?v=H2tuKiiznsY

MCAS=May Crash Any Second.
Oh dear, Boeing has its work cut out for them.
Personally, viewing all the reports, videos & comments, the FAA will see the world's civil aviation authorities watching them to see how fast they allow the 737 Max to re-enter service.
Boeing only got to be the No 1 manufacturer due to it being subsidised by the States. Sadly, it took 2 fatal incidents to put them in the spotlight. From what has been seen by many of the worlds leading aviation experts & experienced pilots so is the FAA.
Not worry Boeing, Trump will save your blushes.

A few of the comments I've made here seem to be shared by others below the video.
https://www.youtube.com/watch?v=H2tuKiiznsY

Thanks for that YouTube vid. It gives a good summary of the most likely mechanical/system cause of the disasters (MCAS), but also shows the competitive pressure likely behind how the whole of modern aviation has been brought into deadly disrepute.

Boeing's claims that their 737 MAX aircraft behaved the same as their previous 737s, and the excuse for the lack of training, was questioned by a certified 737 instructor for Ethiopian Airlines:


Long Before Boeing 737 Max Crash, Ethiopian Air Pilot Warned of Dangers

An Ethiopian Airlines pilot told senior managers at the carrier months before one of its Boeing Co. 737 Max jets crashed that more training and better communication to crew members was needed to avert a repeat of a similar disaster involving a Lion Air flight...

... the pilot in December urged his superiors to bolster training on a 737 Max flight-control feature so crews would be better prepared for what the Lion Air pilots encountered in October before plunging into the Java Sea, killing all aboard. “It will be a crash for sure” if pilots struggling with a malfunction of Boeing’s flight-control system on the 737 Max also encountered, for example, a cockpit warning that they were flying too close to the ground...

... he resigned from the airline after he had “previously raised concerns with Ethiopian Airlines that in Capt. von Hoesslin’s opinion were not adequately addressed, and his concerns related to very serious matters of aircraft safety,”...

... In the December email, von Hoesslin reminded managers that flight crews could be overwhelmed by multiple warnings and cockpit alerts that can sound during an errant activation of MCAS...

... von Hoesslin called attention to the airline’s flight simulator program. The simulators were based on Boeing’s earlier 737 “Next Generation,” or NG, family of jets, and the program didn’t replicate MCAS...

MCAS=May Crash Any Second.
Oh dear, Boeing has its work cut out for them.
Personally, viewing all the reports, videos & comments, the FAA will see the world's civil aviation authorities watching them to see how fast they allow the 737 Max to re-enter service.
Boeing only got to be the No 1 manufacturer due to it being subsidised by the States. Sadly, it took 2 fatal incidents to put them in the spotlight. From what has been seen by many of the worlds leading aviation experts & experienced pilots so is the FAA.
Not worry Boeing, Trump will save your blushes.

To my personal view, there is a lot of disrepute to overcome there...

I'm certainly not flying anything Boeing until at least a year after all this has satisfactorily settled down.

Also good for the planet even if my travel may well be a little curtailed...


All in our only one world,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)