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Old 16th March 2019, 19:50   #91
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Default re: Boeing 737 Max crashes and grounding

Interesting article relating to the issue under discussion which seems to suggest that there is a fundamental design issue:

https://www.linkedin.com/pulse/case-...postolidis-phd
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Old 16th March 2019, 20:27   #92
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Quote:
Originally Posted by HyperRetard View Post
Because MCAS works on sensors, and the sensors malfunctioned.
The sensors believed that the plane was stalling, so they automatically pushed the nose down and increased the engine speed, to prevent the engines from stalling.
.
Just a small correction, stall discussed here has nothing to do with engine stalling.

Quote:
Stalls in fixed-wing flight are often experienced as a sudden reduction in lift as the pilot increases the wing's angle of attack and exceeds its critical angle of attack (which may be due to slowing down below stall speed in level flight). A stall does not mean that the engine(s) have stopped working, or that the aircraft has stopped moving
Source

In other words, aircraft losing lift.

Last edited by ecenandu : 16th March 2019 at 20:29.
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Old 16th March 2019, 20:36   #93
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Default re: Boeing 737 Max crashes and grounding

Quote:
Originally Posted by ecenandu View Post
Just a small correction, stall discussed here has nothing to do with engine stalling.


Source

In other words, aircraft losing lift.

I know what aerodynamic stall is, and what lift is, and how it is generated.
Unless, ofcourse you were correcting it for someone else.
Ofcourse, there is no automotive equivalent for the same, so, yeah, the analogies can get a bit weird,
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Old 17th March 2019, 01:00   #94
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Default re: Boeing 737 Max crashes and grounding

Quote:
Originally Posted by Jeroen View Post
If you are in charge, what would your recommendations be narrowed down to three simple options:

- Train/instruct pilots better and more?
- Automate less, because obviously one crew could not deal with it
- Automate more, in order to exclude human error in this manner

Most likely the more automation option gives a better improvement over the first two.

These things are hugely complex, but less automation is not necessarily the best solution.
Jeroen
Reliability is another dimension. More automation can be a better solution only if it is reliable. As many of us would know, 'Reliability Engineering' is a subject by itself and aeronautical /aerospace industries have contributed to / benefited from this subject.

So we expect the new automation to have undergone a close scrutiny and testing for reliability before sending it to the market, irrespective of the commercial / competitive pressure.
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Old 17th March 2019, 07:35   #95
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Default re: Boeing 737 Max crashes and grounding

After 2 Crashes of New Boeing Jet, Pilot Training Now a Focus

One area of focus is whether the training procedures on Boeing’s jet, greenlighted by the Federal Aviation Administration, left pilots unprepared to deal with new software on the plane. When the plane was introduced, Boeing believed that pilots who had flown an earlier model didn’t need additional simulator training and regulators agreed. The F.A.A. didn’t change those rules after the Lion Air crash in October and there are no plans to do so now.

https://www.nytimes.com/2019/03/16/b...-lion-air.html
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Old 17th March 2019, 08:15   #96
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Default re: Boeing 737 Max crashes and grounding

There is a report that the investigators have found a piece of a stabiliser in the wreckage, with the trim set in an unusual position similar to that of the Lion Air aircraft.

https://amp.scroll.in/latest/916694/...-plane-reuters
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Old 17th March 2019, 08:34   #97
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1. Boeing to roll out software update in 10 days.

2. To be signed off by FAA.

3. Installation to take 2 hours for each plane.

https://www.google.co.in/amp/s/www.c...n-10-days.html

Last edited by AMG Power : 17th March 2019 at 09:02.
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Old 18th March 2019, 09:40   #98
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Default re: Boeing 737 Max crashes and grounding

Quote:
Originally Posted by HyperRetard View Post
The sensors believed that the plane was stalling, so they automatically pushed the nose down and increased the engine speed, to prevent the engines from stalling.
From the articles available, the MCAS do not increase thrust. It simply pushes the nose down so that the aircraft does not stall.
http://www.b737.org.uk/mcas.htm
https://theaircurrent.com/aviation-s...em-mcas-jt610/


Quote:
Originally Posted by HyperRetard View Post
The sensors believed that the plane was stalling, so they automatically pushed the nose down and increased the engine speed, to prevent the engines from stalling.
I believe that ecenandu was correcting the highlighted part in your post.

Last edited by A350XWB : 18th March 2019 at 09:47.
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Old 18th March 2019, 17:50   #99
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Default re: Boeing 737 Max crashes and grounding

U.S. Transportation Department inspector general investigating FAA's approval of Boeing 737 Max

https://edition.cnn.com/2019/03/17/p...ion/index.html

A Wall Street Journal report shared by CNN

This is serious.
Quote:
An excerpt....

The Transportation Department's Inspector General has opened an investigation into the Federal Aviation Administration's approval of Boeing's 737 Max planes, the Wall Street Journal reported Sunday.

The Journal's report of the inspector general's probe comes after the 737 Max planes were grounded for an indefinite period globally last week in the wake of two deadly accidents involving the aircraft model.

The investigation will be focused on an automatic safety system implicated in the October crash involving Lion Air in Indonesia, the Journal reported, citing a government official.

It is unknown if the Ethiopian Airlines flight that crashed a week ago will play any role in this investigation or not.

The Journal reported, citing a source familiar with the matter, that a subpoena has been issued by a grand jury in Washington seeking "documents, includng correspondence, emails and other messages" from at least one person involved in the development of the 737 Max planes. CNN has not been able to independently verify that a subpoena was issued.

CNN has reached out to the Transportation Department and the agency's inspector general's office for comment.
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Old 18th March 2019, 20:14   #100
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Default re: Boeing 737 Max crashes and grounding

Quote:
Originally Posted by V.Narayan View Post
This is serious.
Indeed!

I found a very detailed report in The Seattle Times

There are various questions raised on the certification of the aircraft. This dust is not going to settle anytime soon.

With the software fix and simple disabling the MCAS within limits of safe operations should resolve the issue but the trust is lost!

An excerpt:

Quote:
As Boeing hustled in 2015 to catch up to Airbus and certify its new 737 MAX, Federal Aviation Administration (FAA) managers pushed the agency’s safety engineers to delegate safety assessments to Boeing itself, and to speedily approve the resulting analysis.

The safety analysis:

- Understated the power of the new flight control system, which was designed to swivel the horizontal tail to push the nose of the plane down to avert a stall. When the planes later entered service, MCAS was capable of moving the tail more than four times farther than was stated in the initial safety analysis document.
- Failed to account for how the system could reset itself each time a pilot responded, thereby missing the potential impact of the system repeatedly pushing the airplane’s nose downward.
- Assessed a failure of the system as one level below “catastrophic.” But even that “hazardous” danger level should have precluded activation of the system based on input from a single sensor — and yet that’s how it was designed.
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Old 18th March 2019, 20:49   #101
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Default re: Boeing 737 Max crashes and grounding

BEA Press Release - 18 Mar 2019.

Quote:
During the verification process of the FDR data, clear similarities were noted by the investigation team between Ethiopian Airlines Flight 302 and Lion Air Flight 610, which will be the subject of further study during the investigation.
Attached Thumbnails
Boeing 737 Max crashes and grounding-bea.jpg  


Last edited by airbus : 18th March 2019 at 20:52.
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Old 18th March 2019, 22:04   #102
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Default re: Boeing 737 Max crashes and grounding

^^^^^
^^^^^
Thanks to @surjaonwheelz for pointing us to the article in the paper - Seattle Times. Those who have the time please go through the long article. For those who may not feel inclined quoted below are some relevant paragraphs. If this is true then we are looking at a serious systemic problem.

Quote:
The FAA, citing lack of funding and resources, has over the years delegated increasing authority to Boeing to take on more of the work of certifying the safety of its own airplanes.

Early on in certification of the 737 MAX, the FAA safety engineering team divided up the technical assessments that would be delegated to Boeing versus those they considered more critical and would be retained within the FAA.

But several FAA technical experts said in interviews that as certification proceeded, managers prodded them to speed the process. Development of the MAX was lagging nine months behind the rival Airbus A320neo. Time was of the essence for Boeing.

A former FAA safety engineer who was directly involved in certifying the MAX said that halfway through the certification process, “we were asked by management to re-evaluate what would be delegated. Management thought we had retained too much at the FAA.”

“There was constant pressure to re-evaluate our initial decisions,” the former engineer said. “And even after we had reassessed it … there was continued discussion by management about delegating even more items down to the Boeing Company.”

Even the work that was retained, such as reviewing technical documents provided by Boeing, was sometimes curtailed.

“There wasn’t a complete and proper review of the documents,” the former engineer added. “Review was rushed to reach certain certification dates.”

When time was too short for FAA technical staff to complete a review, sometimes managers either signed off on the documents themselves or delegated their review back to Boeing.
@airbus, thank you for pasting the BEA's letter. For those who may not know after USA, it is France that is today the second nation in aviation. And that's why Ethiopian Airlines chose to send the black box to France and not USA to get a opinion that is unbiased in every way.

Certifying an aircraft is a long and meticulous process. There is so much to do that the work is divided into (A) routine & non-critical things that will often be delegated to a special team formed from within the OEM (B) some critical but not hazardous items or items requiring a very specialist skill that are handed over to independent consultants that assist the regulator (C) the items linked to flight safety that the regulator handles itself.

If what the Seattle Times writes is true then we are staring at a very deep problem. Over the last two decades EASA (European Aviation Safety Agency) has emerged, based on my direct experience, as the gold standard amongst regulators. One reason is that they are autonomous and not affiliated to any Govt or nation. If the FAA has been contaminated by these 'practical' pressures then the whole aviation industry worldwide is the loser because we all depend on the credibility of FAA and EASA to fly aeroplanes.

Last edited by V.Narayan : 18th March 2019 at 22:07.
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Old 18th March 2019, 22:51   #103
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Default re: Boeing 737 Max crashes and grounding

Compromises at Boeing? Saw this 5 year old YT Al Jazeera documentary -



As a commenter on YT said - 'If it's a Boeing, I'm not going'.

It's time to investigate the 737 MAX design and production right down to the minutest detail.
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Old 18th March 2019, 23:02   #104
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Default re: Boeing 737 Max crashes and grounding

Classic case of Principal-Agent Problem, as moderator Samurai quotes often.

Facts of individual accidents aside, a manufacturer having the ability to authorize items on the safety certification of their own product is an enormous red flag in and of itself. We can debate the process all day, but the fact that classification of critical vs. non-critical items on said certification could be based on considerations other than safety alone, renders the argument moot.

I understand from more learned aviation contributors on the forum that collaborating with OEMs on safety certifications is standard procedure, but I find it absurd that there's any plausible scenario where a responsible regulator will consider safety as secondary to another factor in the consideration set, time-to-market being an apparent contributor in Boeing's case.

If the possibility to cut corners exists, it's a matter of when, not if, it will be explored and implemented. Human nature, unfortunately.

Last edited by Chetan_Rao : 18th March 2019 at 23:09.
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Old 18th March 2019, 23:10   #105
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Default re: Boeing 737 Max crashes and grounding

Although team Bhp is an automotive forum, the quality of content in the aviation space within team Bhp is at a much higher level than that in the automotive space.

One of the reasons could be that aviation has far more detail at a technical, regulatory and commercial level than automobiles.

The second is that content quality doesn't get diluted as threads can't be opened on " How many planes have you seen with similar shaped tail lights?".

The third is that contribution is confined to serious content and not individual posts stating "I think the Regent Blue colour suits that plane better".

Net, we have a forum where content quality cannot be diluted.
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