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Boeing Shares Plunge and Recover Post Plane Crash

 
 
 
barbos said:
Barbos, MCAS (Maneuvering Characteristics Augmentation System) systems have been around for a while now
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Not according everything on the internet.
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I first heard that acronym a few years ago, since I've been working with internal aircraft documentation, but it is possible that the use of the acronym was not used in earlier versions of the anti-stall flight control systems.

barbos said:
MCAS was introduced by Boeing on the 737 Max 8 because its heavier, more fuel-efficient engines changed the aerodynamic qualities of the workhorse aircraft and can cause the plane's nose to pitch up in certain conditions during manual flight.
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https://phys.org/news/2019-03-ethiopian-airlines-mcas-boeing-max.html

It did not exist prior to MAX 8, and it was not described in the MAX 8 manual. And it certainly does not exist in any other plane, which simply warn pilots about stall and expect pilot to react.
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All fly-by-wire aircraft have similar systems for controlling flight envelope and preventing pilots from pitching the aircraft into a stall. (See  Flight envelope protection) Companies will attach various names to them, and the Max aircraft needed a major redesign because of the nose-heavy weight distribution. I did work with some of the 737 flight deck engineers and pilots on terminology and even piloted the 737 NG simulator. (Unfortunately, I crashed, but I once successfully avoided a crash in the 777 simulator.) Since aircraft versions are developed years ahead of time, I may have become familiar with that term a lot earlier than people outside of the company.
 
Copernicus said:
I first heard that acronym a few years ago, since I've been working with internal aircraft documentation, but it is possible that the use of the acronym was not used in earlier versions of the anti-stall flight control systems.

barbos said:
MCAS was introduced by Boeing on the 737 Max 8 because its heavier, more fuel-efficient engines changed the aerodynamic qualities of the workhorse aircraft and can cause the plane's nose to pitch up in certain conditions during manual flight.
Click to expand...
https://phys.org/news/2019-03-ethiopian-airlines-mcas-boeing-max.html

It did not exist prior to MAX 8, and it was not described in the MAX 8 manual. And it certainly does not exist in any other plane, which simply warn pilots about stall and expect pilot to react.
Click to expand...

All fly-by-wire aircraft have similar systems for controlling flight envelope and preventing pilots from pitching the aircraft into a stall. (See  Flight envelope protection) Companies will attach various names to them, and the Max aircraft needed a major redesign because of the nose-heavy weight distribution. I did work with some of the 737 flight deck engineers and pilots on terminology and even piloted the 737 NG simulator. (Unfortunately, I crashed, but I once successfully avoided a crash in the 777 simulator.) Since aircraft versions are developed years ahead of time, I may have become familiar with that term a lot earlier than people outside of the company.
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You are trying to BS me. MCAS is a new system which even have a mechanical switch pilots did not know about enough.
None of that exists on any other plane. It is simply not needed there. Pilots were not amused by the way it appeared.

In any case It seems MCAS is to blame for the second crash as well. Boeing is in deep shit.
 
Sounds like United, Southwestern, American and other major U.S. carriers are voluntarily grounding their MAX 8 airplanes
 
TSwizzle said:
Copernicus said:
I had lunch with some Boeing colleagues today and got more insight into what is happening with the Max 8. It turns out that the original design of the 737 had a feature that automatically cut out the anti-stall system. When the pilot pulled back sharply on the yoke, that would take the aircraft to manual control. The new system installed on the Max 8 and 9 removed that feature and replaced the cut-out with two switches that need to be set. So some pilots may be pulling back on the yoke, expecting the autopilot to shut down, and forgetting to use the switches. There have been more incidents with the anti-stall system after takeoff in the US, but pilots have always managed to shut down the autopilot when that happened. Moreover, the yoke is now much harder to resist than it was in the past, if the pilot does not override the autopilot. An investigation must still verify that this was the problem with the Ethiopia crash.

The new system actually uses two sensors, but the software was designed to rely on readings from just one of the sensors. The new fix, which was originally supposed to be deployed in January, has more redundancy built into the system so that the MCAS has to resolve discrepancies. However, the fix has yet to be fully tested before deployment. So the new date is set for next month (April).
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Very interesting. I also read somewhere that this aircraft has the MCAS because the center of gravity of the plane shifted due to a heavier engine installed further forward on the wing. If true, isn't that a design flaw in itself ? Just curious.
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Based on statics, it isn't an issue as long as you know the weight distribution and design for it.

Also, I heard that Boeing were going to deliver aircraft with a dog installed in the cockpit. The pilot will be there to feed the dog and the dog will bite the pilot if he touches anything. (The old ones are the best ones. :p)
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That was Airbus.
 
barbos said:
You are trying to BS me. MCAS is a new system which even have a mechanical switch pilots did not know about enough.
None of that exists on any other plane. It is simply not needed there. Pilots were not amused by the way it appeared.

In any case It seems MCAS is to blame for the second crash as well. Boeing is in deep shit.
Click to expand...

MCAS is a new safety feature that was introduced in the new 737 max line to counter the increase in engine size and change in engine location to a more forward position in the max line. The problem was that Boeing did not sufficiently highlight the operation of the MCAS system in their training material, and many/most pilots flying the max hardware were not even aware of the MCAS system operation prior to the Lion Air crash.

The MCAS system intervenes in certain situations when the aircraft is in manual flight mode (autopilot off), in an effort to prevent the aircraft from stalling. In the Lion Air crash, the flight computer was receiving faulty data from the AOA sensors which detect the inclination of the wings relative to the horizontal. The AOA sensors were reporting an erroneous stall condition (nose pushed too far up), which activated the trim stabilizers at the back to force the nose down. The MCAS system can be switched off using switches that control trim using the flight computer (switches located below the flap lever), and pilots can adjust the stabilizers manually using the trim wheels. The Lion Air pilots involved in the crash were apparently not aware of the MCAS system, and they were faced with multiple error messages once MCAS had engaged; they tried to override the trim set by MCAS multiple times using the yoke, but did NOT switch off the auto trim feature. Ultimately, the nose was pushed down too far for the pilots to regain control which caused the crash.

Following the findings of the Lion Air crash, both the FAA and Boeing issued briefs highlighting the operation of the MCAS system, and most pilots flying 737 max hardware today should be aware of the feature, and how to counteract any unintended behavior (auto trim off, use trim wheels manually to set the angle of attack). It is possible that the Ethiopian crash was also caused by MCAS. The aircraft had apparently climbed to just about 6,000 feet before it crashed, which would leave the crew very little time to react, much less run checklists.
 
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barbos said:
RavenSky said:
Sounds like United, Southwestern, American and other major U.S. carriers are voluntarily grounding their MAX 8 airplanes
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Well, Trump grounded them all, this is a case where I agree with Trump
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Well, the big carriers grounded themselves after the FAA said they wouldn't.

THEN the FAA belated did what the rest of the world and our major carriers already did.

Trump didn't do shit. In fact, Trump has failed to even appoint anyone as the head of the FAA... i.e. someone to deal with this crisis.
 
Apparently multiple U.S. pilots have reported similar sudden nose-down while on autopilot in the last several months.

(And Maddow's report regarding the chief executive of Boeing - who is vying for the FAA position - pressuring Trump and the FAA NOT to ground the planes in the U.S. if frelling scary)
 
barbos said:
Copernicus said:
I first heard that acronym a few years ago, since I've been working with internal aircraft documentation, but it is possible that the use of the acronym was not used in earlier versions of the anti-stall flight control systems.

All fly-by-wire aircraft have similar systems for controlling flight envelope and preventing pilots from pitching the aircraft into a stall. (See  Flight envelope protection) Companies will attach various names to them, and the Max aircraft needed a major redesign because of the nose-heavy weight distribution. I did work with some of the 737 flight deck engineers and pilots on terminology and even piloted the 737 NG simulator. (Unfortunately, I crashed, but I once successfully avoided a crash in the 777 simulator.) Since aircraft versions are developed years ahead of time, I may have become familiar with that term a lot earlier than people outside of the company.
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You are trying to BS me. MCAS is a new system which even have a mechanical switch pilots did not know about enough.
Click to expand...

The MCAS is a software system that acquired a new acronym well before it came to public attention. Such names usually originate with the design engineers and get propagated through a document stream that includes engineering, manufacturing, maintenance & repair, and business (including marketing) documentation. It usually takes a few years before the name gets released to the public. While MCAS is an acronym for a specific flight control system, it is part of a family of avionics programs that control the flight envelope in fly-by-wire aircraft. The whole point of such aircraft is to automate the flight envelope during various phases of flight. Apparently, the software developed for the MCAS had to do with the nose-heavy configuration of MAX 8 and 9 aircraft.

barbos said:
None of that exists on any other plane. It is simply not needed there. Pilots were not amused by the way it appeared.
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Barbos, how could you possibly know what attitude pilots had regarding the MCAS? Do you even know any pilots? I do. Given the new center of gravity in the aircraft, pilots would definitely not have been amused if Boeing had NOT developed new software to address the new flight configuration. In fact, the aircraft could not possibly have been certified without new software to address that issue. The engineers who designed the new system likely had very good reasons for discontinuing the earlier method of disconnecting the autopilot during ascent to cruising altitude. I don't know the details of why they did it, and neither do you. All we know is that pilots experienced difficulties with malfunctions in that system after the aircraft were deployed.

Something I have been reading about has intrigued me, because I spent a couple of years working on a project with the 737 Flight Crew Operation Manuals and checklists. The reason our team was called in was that we were linguists with special knowledge about language issues in technical documentation in our industry. Boeing was trying to improve the clarity of language in operating manuals to satisfy customer requests for those improvements. My own specialization was a maintenance documentation standard called ASD Simplified Technical English (STE), which was not mandatory for flight operation manuals. It turns out that Airbus had adapted a version of that standard to their flight operations manuals, and Boeing was looking for suggestions. The advantage of STE is that it clarifies the English of technical documentation, especially technical documentation. And it has become something of a standard across a wide range of manufacturing industries even outside of aerospace.

Both of the Max 8 crashes happened with non-English speaking carriers--Indonesian and Ethiopian. So the native language of the host countries was, respectively, Indonesian and Amharic. (That does not tell us what the native language of the pilots was.) It turns out that Ethiopian Airlines claims that they felt the language giving description and instructions for the MCAS was unclear. That doesn't surprise me, but I would love to have seen the language they were referring to and whether they had asked the company for clarification. It would surprise me to learn that their pilots were certified without some specified number of hours in a simulator, which would have simulated an engine stall. Pilots also refer to Nonnormal Checklists during unusual incidents in the course of a flight, but the checklists can use quite telegraphic language (therefore, cryptic to some pilots without native competence in English). I have no prejudgments on whether language was an issue here, but it does make me curious, given my former role in the company. I do wish that Boeing had adopted STE for flight operation manuals (FCOMs), but there was too much resistance to the idea for that to happen. Airbus, a much younger company with less aircraft documentation to maintain, did adapt STE to operations manuals.
 
atrib said:
barbos said:
You are trying to BS me. MCAS is a new system which even have a mechanical switch pilots did not know about enough.
None of that exists on any other plane. It is simply not needed there. Pilots were not amused by the way it appeared.

In any case It seems MCAS is to blame for the second crash as well. Boeing is in deep shit.
Click to expand...

MCAS is a new safety feature that was introduced in the new 737 max line to counter the increase in engine size and change in engine location to a more forward position in the max line. The problem was that Boeing did not sufficiently highlight the operation of the MCAS system in their training material, and many/most pilots flying the max hardware were not even aware of the MCAS system operation prior to the Lion Air crash.

The MCAS system intervenes in certain situations when the aircraft is in manual flight mode (autopilot off), in an effort to prevent the aircraft from stalling. In the Lion Air crash, the flight computer was receiving faulty data from the AOA sensors which detect the inclination of the wings relative to the horizontal. The AOA sensors were reporting an erroneous stall condition (nose pushed too far up), which activated the trim stabilizers at the back to force the nose down. The MCAS system can be switched off using switches that control trim using the flight computer (switches located below the flap lever), and pilots can adjust the stabilizers manually using the trim wheels. The Lion Air pilots involved in the crash were apparently not aware of the MCAS system, and they were faced with multiple error messages once MCAS had engaged; they tried to override the trim set by MCAS multiple times using the yoke, but did NOT switch off the auto trim feature. Ultimately, the nose was pushed down too far for the pilots to regain control which caused the crash.

Following the findings of the Lion Air crash, both the FAA and Boeing issued briefs highlighting the operation of the MCAS system, and most pilots flying 737 max hardware today should be aware of the feature, and how to counteract any unintended behavior (auto trim off, use trim wheels manually to set the angle of attack). It is possible that the Ethiopian crash was also caused by MCAS. The aircraft had apparently climbed to just about 6,000 feet before it crashed, which would leave the crew very little time to react, much less run checklists.
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Yes, tha's all correct and is what I am saying too.
 
barbos said:
Copernicus, you are defending Boeing.
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Pointing out your errors of fact doesn't constitute a defence of Boeing.

Whether they require defending remains to be seen, and your assumption that they do is as unsubstantiated as your assumption that Copernicus is doing so.
 
bilby said:
barbos said:
Copernicus, you are defending Boeing.
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Pointing out your errors of fact doesn't constitute a defence of Boeing.

Whether they require defending remains to be seen, and your assumption that they do is as unsubstantiated as your assumption that Copernicus is doing so.
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What is wrong with you?
I merely parroted things which was widely reported and confirmed by many in the industry. Here comes Copernicus and his secret Boeing buddies and contradict all of that.
 
barbos said:
bilby said:
barbos said:
Copernicus, you are defending Boeing.
Click to expand...

Pointing out your errors of fact doesn't constitute a defence of Boeing.

Whether they require defending remains to be seen, and your assumption that they do is as unsubstantiated as your assumption that Copernicus is doing so.
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What is wrong with you?
I merely parroted things which was widely reported and confirmed by many in the industry. Here comes Copernicus and his secret Boeing buddies and contradict all of that.
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You made a bunch of unsubstantiated claims. Including the claim that Copernicus was 'defending Boeing'.

You haven't given any reason why anyone should agree with you; Widely reported where? Who are the 'many in the industry who confirmed these alleged reports?

It's not enough that you are convinced that you are correct; If you care about other people's opinions on these boards, you must convince us. (If you don't care, why post at all?).
 
bilby said:
barbos said:
What is wrong with you?
I merely parroted things which was widely reported and confirmed by many in the industry. Here comes Copernicus and his secret Boeing buddies and contradict all of that.
Click to expand...

You made a bunch of unsubstantiated claims. Including the claim that Copernicus was 'defending Boeing'.

You haven't given any reason why anyone should agree with you; Widely reported where? Who are the 'many in the industry who confirmed these alleged reports?

It's not enough that you are convinced that you are correct; If you care about other people's opinions on these boards, you must convince us. (If you don't care, why post at all?).
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Something is definitely wrong with you today.
 
Although the investigation is far from complete, it seems that an important safety feature is available as a paid option on the 737 MAX and neither of these planes had it installed. WTF is that all about ?!

Trevor Noah begs the question, "How was a self-crashing plane allowed to fly?"

Teh Grauniad
 
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