sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 6:36 pm

XRAYretired wrote:
JetBuddy wrote:
New article today in reputable Wall Street Journal.

The Four-Second Catastrophe: How Boeing Doomed the 737 MAX

"In designing the flight controls for the 737 MAX, Boeing assumed that pilots trained on existing safety procedures should be able to sift through the jumble of contradictory warnings and take the proper action 100% of the time within four seconds.

That is about the amount of time that it took you to read this sentence."



https://www.wsj.com/articles/the-four-s ... 1565966629

If you've used up your "free" articles, you can sometimes google the title and be able to read it anyway.

Free to view carbon......Damning......
https://ih.advfn.com/stock-market/NYSE/ ... doomed-the

Ray


The wording is still too lenient on Boeing:

"In designing the flight controls for the 737 MAX, Boeing assumed that pilots trained on existing safety procedures should be able to sift through the jumble of contradictory warnings and take the proper action 100% of the time within four seconds."

There's enough evidence pointing to Boeing using pilot assumptions as a vehicle for safety classification, single sensor design, and certification, rather than the other way around.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
MSPNWA
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 6:44 pm

JetBuddy wrote:
New article today in reputable Wall Street Journal.


Personally, I don't consider a sensationalist article devoid of highly relevant facts (that could lead readers to different conclusions (meaning it's biased)) as reputable.

Sadly the WSJ isn't immune from sensationalist "journalism". Even with some good nuggets in the article, the slant is plainly obvious to those with knowledge of the crashes. The public without that knowledge however, they're essentially being lied to.
 
MrBretz
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 6:50 pm

MSPNWA, please elaborate.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 6:51 pm

XRAYretired wrote:
Free to view carbon......Damning......
https://ih.advfn.com/stock-market/NYSE/ ... doomed-the

Some things that caught my eye.

"Our marching orders are no training impact on this airplane. Period," Richard Reed, a former Federal Aviation Administration engineer, recalled a senior Boeing official telling him during a meeting in the early years of the MAX's development.

Seems Mr Reed should have brought this type of pressure-laden statement up with his superiors in the FAA.

Hopefully Mr. Reed is naming names to the various investigators so this angle of the case can be investigated.

If I were part of the FBI/DoJ probe, this kind of pre-determination would draw a lot of my attention.

The FAA is reassessing some of its key assumptions. The agency said certification procedures are "well-established and have consistently produced safe aircraft designs," but it is rethinking reliance on average U.S. pilot reaction times as a design benchmark for planes that are sold in parts of the world with different experience levels and training standards.

Cue the chorus of taunts accusing the FAA of exceptionalism/jingoism/racism/etc.

Et tu, FAA?
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sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 6:52 pm

XRAYretired wrote:
JetBuddy wrote:
New article today in reputable Wall Street Journal.

The Four-Second Catastrophe: How Boeing Doomed the 737 MAX

"In designing the flight controls for the 737 MAX, Boeing assumed that pilots trained on existing safety procedures should be able to sift through 8the jumble of contradictory warnings and take the proper action 100% of the time within four seconds.

That is about the amount of time that it took you to read this sentence."



https://www.wsj.com/articles/the-four-s ... 1565966629

If you've used up your "free" articles, you can sometimes google the title and be able to read it anyway.

Free to view carbon......Damning......
https://ih.advfn.com/stock-market/NYSE/ ... doomed-the

Ray


Also too lenient:

"The assumptions dovetailed with a vital company goal. To make the plane as inexpensive as possible for airlines to adopt..."

More likely that Boeing needed to keep promises made by marketing engineers to airlines. I cant readily recall the source but isnt it fact that Boeing promised no simulator time?
Last edited by sgrow787 on Fri Aug 16, 2019 6:55 pm, edited 1 time in total.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 6:54 pm

sgrow787 wrote:
More likely that Boeing needed to keep promises made by marketing engineers to airlines. I cant readily recall the source but isnt it fact that Boeing promised no simulator time?

It's in Ray's link:

The company had promised its biggest customer for the MAX, Southwest Airlines Co., that it would pay it $1 million per plane ordered if pilots needed to do additional simulator training, according to Rick Ludtke, a Boeing engineer who worked on the jet's cockpit systems, and another person who had been involved in the airplane's development.
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sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 7:07 pm

Revelation wrote:
sgrow787 wrote:
More likely that Boeing needed to keep promises made by marketing engineers to airlines. I cant readily recall the source but isnt it fact that Boeing promised no simulator time?

It's in Ray's link:

The company had promised its biggest customer for the MAX, Southwest Airlines Co., that it would pay it $1 million per plane ordered if pilots needed to do additional simulator training, according to Rick Ludtke, a Boeing engineer who worked on the jet's cockpit systems, and another person who had been involved in the airplane's development.


I should probably completely finish the article before commenting next time. But I still think WSJ could have worded it differently.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
TheF15Ace
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 7:42 pm

sgrow787 wrote:
TheF15Ace wrote:
bennett123 wrote:
If it was primarily a training issue, would they still be grounded?.


Wouldn't have been grounded to begin with


Yes, it would have been grounded still, assuming the one sensor design was discovered (assuming pilots would have been made aware of the MCAS v1.0 system). And even as Sully pointed out, even with proper training, the startel factor from being so close to the ground points to the need for reclassification of safety level, which in turn results in two sensor redesign.


Maybe I should rephrase. Were it up to the FAA/Boeing with foreign regulators following the FAA's lead (as they did with initial certification) it wouldn't have been grounded. After ET302 the FAA issued a Continued Airworthiness Notification to the International Community
(https://www.faa.gov/news/updates/media/CAN_2019_03.pdf) stating that following the crash of JT610 they have among other things

Reviewed Boeing’s production processes related to the AOA vane and Maneuvering Characteristics
Augmentation System (MCAS)


I'd assume that at that point the one sensor design and all that comes with it would've been glaringly obvious to the FAA. Yet they felt the EAD was adequate to continue operations while Boeing would work on a fix, and weren't in a rush (or willing at all, depends on who you ask) to ground even after a second crash under the same circumstances.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 7:48 pm

XRAYretired wrote:
planecane wrote:
XRAYretired wrote:
Polarised lenses must have been in last time.

http://www.avherald.com/h?article=4c534c4a/0045&opt=0
'the first 737-8 MAX simulator was put into service mid January 2019. Only in March 2019 a trim runaway lesson was included in the NG and MAX training syllabus. Flight crew are scheduled to go through a simulator session every 6 months (as per industry standards), '

From <https://www.airliners.net/forum/search.php?keywords=syllabus&t=1421471&sf=msgonly>

Ray


Thank you for the reference. That appears to be specific to ET. To me, that indicates a huge issue with the training at ET (and possibly other airlines). How can something that has an NNC and is considered important enough to be a memory item not be included in the training syllabus?

Training syllabus is a Boeing responsibility.

Ray


Guess I musta been confused about what I was doing in the simulator for 30 years. I believe Boeing provides guidelines but it’s between the airline and their regulatory authority to decide what they want to do.
 
akb88
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 7:57 pm

Icelandair not expecting them to fly again until next year. Dropping PDX for the winter schedule while increasing shorter Europe routes such as DUB, CPH and BRU
Only yesterday the CEO said he expected them back in mid-October.
 
IADFCO
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 8:02 pm


Maybe it's useful to remember, every once in a while, where everything started from. Is it just the extra lift from the bigger nacelle, or is it a more fundamental disruption of the flow field on a broad spanwise segment of the wing leading edge?
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 8:24 pm

XRAYretired wrote:
JetBuddy wrote:
New article today in reputable Wall Street Journal.

The Four-Second Catastrophe: How Boeing Doomed the 737 MAX

"In designing the flight controls for the 737 MAX, Boeing assumed that pilots trained on existing safety procedures should be able to sift through the jumble of contradictory warnings and take the proper action 100% of the time within four seconds.

That is about the amount of time that it took you to read this sentence."



https://www.wsj.com/articles/the-four-s ... 1565966629

If you've used up your "free" articles, you can sometimes google the title and be able to read it anyway.

Free to view carbon......Damning......
https://ih.advfn.com/stock-market/NYSE/ ... doomed-the

Ray


Still, the pilots in those simulator sessions responded as expected, people familiar with the results said, executing Boeing's emergency procedure properly and in time.


I quoted this to dispute both the myth of pilots unable to recover in simulators and also to dispute the statement that Boeing was just hoping that they'd get the fix done before the next crash. Just as the article details what led to the bad design (although they wrote "altitude" when it should have been "attitude") it also details that the EAD was evaluated to determine if it would be sufficient to prevent another crash before the fix was complete.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 10:11 pm

planecane wrote:
Is it reasonable to expect the pilots to be the backstop against dual engine failure on takeoff? Sully and the Russian pilot from the other day both handled that emergency which isn't trained for.

Is it reasonable to expect the pilots to be the backstop against an uncontained engine failure simultaneous with a rapid depressurization? Those are two emergencies that individually must be reacted to quickly and correctly if they happen individually. The pilots of WN1380 handled both flawlessly and landed safely.

Is it reasonable to expect the pilots to be the backstop against any emergency situation? If not, what is the job of a pilot? Flying an aircraft in good conditions isn't all that difficult. The skill and airmanship comes into play in non-routine situations and emergencies. Yes, I expect when I board a flight that the pilots are capable of recovering from any emergency situation that is possible to recover from.

Boeing putting out an incompetent design for a system and the pilots not having the training and/or airmanship skills to recover from the failure that resulted from the incompetent design are not mutually exclusive. Boeing's screw up caused two events of runaway stabilizer that otherwise wouldn't have happened. The pilots also didn't recover from a recoverable situation.


Is it reasonable to set up a training system for a one in a BILLION-flight event? A glider still flies, and can be operated (and even land) with reasonably normal flying skills.

Is it reasonable to expect the average Joe Pilot to be the backstop for a one in 100000 flight event with much more catastrophic result, with possible unrecoverable condition (we still don't know why ET crew could not up-trim beyond 2.3 units of stab angle, and yes, they did try, and yes, they did flick the switches . . . ).

The multi order of magnitude difference makes any comparison between these two type of events (dual engine failure, MCAS) totally irrelevant. Besides, history has shown that the general worldwide piloting skills can handle the dual engine failure fairly satisfactory (unlike MCAS). Even Russian pilots can do that, or do you now think Russian aviation is at par with north American standards (look no further than the SuperJet event, to read how some would rather heavily disagree with that position).

If at all, that even supports the position that piloting skills in general are not at issue, it is the specific type that is the odd one out. It seems that MCAS 1.0 in combination with the 737 trim system was too much too handle for most pilots outside Boeing test group.
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 10:23 pm

planecane wrote:
XRAYretired wrote:
Polarised lenses must have been in last time.

http://www.avherald.com/h?article=4c534c4a/0045&opt=0
'the first 737-8 MAX simulator was put into service mid January 2019. Only in March 2019 a trim runaway lesson was included in the NG and MAX training syllabus. Flight crew are scheduled to go through a simulator session every 6 months (as per industry standards), '

From <https://www.airliners.net/forum/search.php?keywords=syllabus&t=1421471&sf=msgonly>

Ray


Thank you for the reference. That appears to be specific to ET. To me, that indicates a huge issue with the training at ET (and possibly other airlines). How can something that has an NNC and is considered important enough to be a memory item not be included in the training syllabus?


Perhaps because it was no longer part of the NG training syllabus. And that, perhaps, was because in the one hundred million NG flights, it was rarely, if ever, needed? Better spend the limited training time to something that is more likely to happen like (dual . . .) engine failure.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 10:36 pm

MrBretz wrote:
MSPNWA, please elaborate.


Yes please.
With such remark, one wonders if he had actually read the article at all.
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MSPNWA
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 16, 2019 11:21 pm

MrBretz wrote:
MSPNWA, please elaborate.


Take just the "four seconds" part. It implies that the pilots have only four seconds under a challenging situation to take the correct action to save the plane. We know that implication is highly misleading at best. In reality the pilots had much more time than four seconds to diagnose and counter an MCAS runaway.

And as usual we have a very sensationalist summary of the cockpit situation that avoids key facts such as none of the problems presented to the pilots should be foreign. They should have had knowledge and been trained on each malfunction, even MCAS. But that wouldn't fit the narrative, so relevant facts have to be left out. The picture is painted that nothing could be expected to be done in the cockpit, which is false.

There's plenty more to mention, including the ubiquitous and false statement of the "nose pitches up" due the engines (strangely they properly talk about stick force later). The presumed typo of "altitude" instead of "attitude" is a big oops. Another is the statement that increasing the MCAS movement to 2.5 degreees "could now lead to a fatal battle between pilot and machine". That's simply not true. The original 0.6 degree adjustment would have also led to a battle, just at a slower pace. We could go on. Reputable? The dictionary tells me this type of writing isn't.

PW100 wrote:
Yes please.
With such remark, one wonders if he had actually read the article at all.


Why don't you ask me yourself instead of hiding behind cover?
 
sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 3:59 am

MSPNWA wrote:
MrBretz wrote:
MSPNWA, please elaborate.


Take just the "four seconds" part. It implies that the pilots have only four seconds under a challenging situation to take the correct action to save the plane. We know that implication is highly misleading at best. In reality the pilots had much more time than four seconds to diagnose and counter an MCAS runaway.

And as usual we have a very sensationalist summary of the cockpit situation that avoids key facts such as none of the problems presented to the pilots should be foreign. They should have had knowledge and been trained on each malfunction, even MCAS. But that wouldn't fit the narrative, so relevant facts have to be left out. The picture is painted that nothing could be expected to be done in the cockpit, which is false.

There's plenty more to mention, including the ubiquitous and false statement of the "nose pitches up" due the engines (strangely they properly talk about stick force later). The presumed typo of "altitude" instead of "attitude" is a big oops. Another is the statement that increasing the MCAS movement to 2.5 degreees "could now lead to a fatal battle between pilot and machine". That's simply not true. The original 0.6 degree adjustment would have also led to a battle, just at a slower pace. We could go on. Reputable? The dictionary tells me this type of writing isn't.

PW100 wrote:
Yes please.
With such remark, one wonders if he had actually read the article at all.


Why don't you ask me yourself instead of hiding behind cover?


We're talking MCAS 1.0 post-Lion here. The 1st iteration of a MCAS cycle is indeterminable from any other automatic AND trim movement. By the 2nd MCAS iteration a knowledgeable pilot might be asking if that was a 5 second interval ( from the last iteration). Its by the 3rd iteration that awareness of MCAS runaway starts or should start to happen. Is there enough time to save the ship after potentially 2 full iterations of MCAS?
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 9:00 am

morrisond wrote:
frmrCapCadet wrote:
I continue to be appalled that there is nothing between an iPod and a $15 million simulator.



Microsoft is bringing back Flight Simulator ...

https://www.xbox.com/en-US/games/micros ... -simulator


I wonder how long it will take someone to bring out the "MCAS failure Mod".
 
uta999
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 9:17 am

Why is the 737-MAX the only aircraft ever to need MCAS? What would a non-MCAS MAX fly like? and could it be any worse than one that has it. Is it simply to mimic the NG in certain flight characteristics? Does it make it safer, easier to fly? Why is removing it completely such an issue? It doesn't work and probably can never be made to work.
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ACATROYAL
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 9:51 am

It simply comes down to the fact the MAX is a variant gone too far. The engines are the main problem... too big , they throw the center of gravity way off creating all sorts of problems talked about to death in this thread...
 
uta999
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 10:38 am

ACATROYAL wrote:
It simply comes down to the fact the MAX is a variant gone too far. The engines are the main problem... too big , they throw the center of gravity way off creating all sorts of problems talked about to death in this thread...


But all this would have manifested itself in the first few hours of both wind-tunnel and then flight testing. Surely someone at Boeing thought if we put bigger engines, further forward it is going to fly like a dog!
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planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 10:50 am

PW100 wrote:
planecane wrote:
Is it reasonable to expect the pilots to be the backstop against dual engine failure on takeoff? Sully and the Russian pilot from the other day both handled that emergency which isn't trained for.

Is it reasonable to expect the pilots to be the backstop against an uncontained engine failure simultaneous with a rapid depressurization? Those are two emergencies that individually must be reacted to quickly and correctly if they happen individually. The pilots of WN1380 handled both flawlessly and landed safely.

Is it reasonable to expect the pilots to be the backstop against any emergency situation? If not, what is the job of a pilot? Flying an aircraft in good conditions isn't all that difficult. The skill and airmanship comes into play in non-routine situations and emergencies. Yes, I expect when I board a flight that the pilots are capable of recovering from any emergency situation that is possible to recover from.

Boeing putting out an incompetent design for a system and the pilots not having the training and/or airmanship skills to recover from the failure that resulted from the incompetent design are not mutually exclusive. Boeing's screw up caused two events of runaway stabilizer that otherwise wouldn't have happened. The pilots also didn't recover from a recoverable situation.


Is it reasonable to set up a training system for a one in a BILLION-flight event? A glider still flies, and can be operated (and even land) with reasonably normal flying skills.

Is it reasonable to expect the average Joe Pilot to be the backstop for a one in 100000 flight event with much more catastrophic result, with possible unrecoverable condition (we still don't know why ET crew could not up-trim beyond 2.3 units of stab angle, and yes, they did try, and yes, they did flick the switches . . . ).

The multi order of magnitude difference makes any comparison between these two type of events (dual engine failure, MCAS) totally irrelevant. Besides, history has shown that the general worldwide piloting skills can handle the dual engine failure fairly satisfactory (unlike MCAS). Even Russian pilots can do that, or do you now think Russian aviation is at par with north American standards (look no further than the SuperJet event, to read how some would rather heavily disagree with that position).

If at all, that even supports the position that piloting skills in general are not at issue, it is the specific type that is the odd one out. It seems that MCAS 1.0 in combination with the 737 trim system was too much too handle for most pilots outside Boeing test group.


First of all, it was an FAA test group, not a Boeing test group.

Regardless, you are missing my point completely. I do not believe that it is acceptable design to have frequent failures but rely on pilots as the "backup." Critical aircraft systems should fail as infrequently as possible.

My point is that I expect pilots to be able to recover from emergency situations that are possible to recover from. It doesn't matter if the emergency happens once in the service life of a model or once a week. The frequency of occurrence shouldn't matter when it comes to pilot's abilities to recover. If MCAS 1.0 had only failed once in the next 30 years of service of the MAX, I would expect the crew of that flight to have been able to recover from it.

No, it is not acceptable to have a design that causes emergencies every 50,000 flights or whatever the rate was with MCAS 1.0. It was a complete failure of both Boeing's internal analysis and FAA oversight that a system was certified that had that failure rate.

This doesn't change the fact that recovery was possible (for sure in the Lion Air case, will need the final ET report to determine if electric trim had the power to get back to being in trim). If recovery from an emergency is possible, my expectation is that the pilots have the training and skill to recover like in the two cases of dual engine failure after takeoff or even loss of both engines in cruise like the Gimli glider.

It won't be possible to recover from all emergencies. If there was a town instead of a corn field then the Russian pilot wouldn't have been able to recover. If the water in the Hudson hadn't been calm, Sully wouldn't have been able to save everybody. A runaway stabilizer at takeoff wouldn't be recoverable. If not for having flaps retracted as a condition for MCAS activation, none of the three flights would have been recoverable.

My point is not that MCAS 1.0 was an acceptable design. It was not. My point is that when I board an aircraft, I am putting my life in the hands of the two people at the controls and I have an expectation that they are trained well enough and have the skills to save my life any time that the possibility exists to do so.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 11:03 am

ACATROYAL wrote:
It simply comes down to the fact the MAX is a variant gone too far. The engines are the main problem... too big , they throw the center of gravity way off creating all sorts of problems talked about to death in this thread...


The problem isn't the center of gravity being too far forward. MCAS is needed because it has a tendency to pitch up under certain conditions. If the center of gravity being too far forward was an issue, it would cause it to pitch down.

The MAX is perfectly stable and doesn't require MCAS or any other automated system in normal flight. It is only under very specific conditions that do not occur during typical operations where the pitch up tendency occurs.

Without MCAS, the MAX would not have passed the wind-up turn test during certification. Outside of that, if MCAS had just been left out, it is very likely that there never would have been an incident caused by the pitch up tendency during an approach to stall under very specific conditions. Pilots should never get to that point in the flight envelope because there will be all kinds of warnings before they reach that point. Mentour pilot had a great video on youtube showing how difficult it is, even on the antiquated 737 with no envelope protection, to get to the point of stalling. Even when he purposely stalled, it was not difficult to recover.
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 11:28 am

planecane wrote:
The MAX is perfectly stable and doesn't require MCAS or any other automated system in normal flight. It is only under very specific conditions that do not occur during typical operations where the pitch up tendency occurs.

Unfortunately, the specifics of the MCAS requirement (specific conditions) has never received a fair hearing, imagine a pdf of the spiral turn or a detailed explanation of what test pilots have to do to put the a/c in the position where they and the FAA determined something had to be done to maintain uniformity with the NG control feel.
In general, anti-stall system is all we need to know.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 11:40 am

par13del wrote:
planecane wrote:
The MAX is perfectly stable and doesn't require MCAS or any other automated system in normal flight. It is only under very specific conditions that do not occur during typical operations where the pitch up tendency occurs.

Unfortunately, the specifics of the MCAS requirement (specific conditions) has never received a fair hearing, imagine a pdf of the spiral turn or a detailed explanation of what test pilots have to do to put the a/c in the position where they and the FAA determined something had to be done to maintain uniformity with the NG control feel.
In general, anti-stall system is all we need to know.


You can read all about the wind up turn (an interesting name since the plane decends) at this link. https://www.scribd.com/document/53095046/NASA-Information-Summaries-Wind-Up-Turn

Also, Lion Air 043 demonstrated that MCAS isn't needed for stability in normal flight since they flew over an hour and landed with manual trim.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 12:22 pm

uta999 wrote:
(1)Why is the 737-MAX the only aircraft ever to need MCAS? (2)What would a non-MCAS MAX fly like? (3)and could it be any worse than one that has it. (4)Is it simply to mimic the NG in certain flight characteristics? (5)Does it make it safer, easier to fly? (6)Why is removing it completely such an issue? (7)It doesn't work and probably can never be made to work.

1) We are told the 767 tanker has MCAS, not sure why since it has the same engines/nacelles as older 767s

2) In a non-MCAS MAX, stick forces would be lighter than FAA regulations allow as the plane approaches a stall under certain specific conditions

3) A non-MCAS MAX would be slightly worse in this scenario, but no one should be near that part of the flight envelope in commercial service

4) No its not about mimicking NG it's about meeting a FAA regulation, but yes, the NG meets that regulation

5) MCAS makes the entry to stall more predictable but again no one should be near that part of the flight envelope in commercial service

6) If MCAS were removed MAX would not meet FAA regulations

7) MCAS 1.0 failed because it trusted sensors that could fail too much and its actions were too aggressive, both of which can and will be fixed.

A post worth repeating:

planecane wrote:
Without MCAS, the MAX would not have passed the wind-up turn test during certification. Outside of that, if MCAS had just been left out, it is very likely that there never would have been an incident caused by the pitch up tendency during an approach to stall under very specific conditions. Pilots should never get to that point in the flight envelope because there will be all kinds of warnings before they reach that point. Mentour pilot had a great video on youtube showing how difficult it is, even on the antiquated 737 with no envelope protection, to get to the point of stalling. Even when he purposely stalled, it was not difficult to recover.

The idea that stick forces should not lighten as stall approaches is a good idea.

Had MCAS 1.0 been properly engineered we probably never would have known it exists.

I bet a year or so from now almost everyone in the traveling public will have forgotten or will ignore that MCAS exists.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 12:31 pm

Revelation wrote:
3) A non-MCAS MAX would be slightly worse in this scenario, but no one should be near that part of the flight envelope in commercial service

A bit of a side comment:
One may argue that no one should have open flames on board, loss of cabin pressure or water landing in normal operations - yet fire extinguishing, oxygen masks and all flavors of flotation devices are mandatory, and actually get used once in a while.
High-reliability systems - like airplanes, nuclear power plants, medical devices etc - need to account for all sorts of abnormal situations to keep that high-reliability status.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:05 pm

Revelation wrote:
1) We are told the 767 tanker has MCAS, not sure why since it has the same engines/nacelles as older 767s

I think this one is easy, its because it is a combination of different 767 models, wings from one version, fuselage from another, so that mix probably changed the dynamics at the required stall thresholds.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:13 pm

kalvado wrote:
Revelation wrote:
3) A non-MCAS MAX would be slightly worse in this scenario, but no one should be near that part of the flight envelope in commercial service

A bit of a side comment:
One may argue that no one should have open flames on board, loss of cabin pressure or water landing in normal operations - yet fire extinguishing, oxygen masks and all flavors of flotation devices are mandatory, and actually get used once in a while.
High-reliability systems - like airplanes, nuclear power plants, medical devices etc - need to account for all sorts of abnormal situations to keep that high-reliability status.

Yes, because open flames breaking out are the same as a few pounds less force on the control stick AFTER stick shaker and horns have been going off for a long time...

Please...

We are talking about basic airmanship here, or the lack of it.

Every pilot gets hard core training about stalling the aircraft and how to not put it into that part of the flight envelope.

If you proceed to do this, and you've ignored the stick shaker and the horns to do so, constant stick force isn't going to help you either.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:15 pm

Revelation wrote:
1) We are told the 767 tanker has MCAS, not sure why since it has the same engines/nacelles as older 767s

The 767 tanker is the Boeing KC-46 Pegasus. It have a MCAS to compensate the fuel displacement due to in air refueling. That KC-46 MCAS is similar to the 737-8/9 MCAS only because both trim the horizontal stabilizer, but the inputs, logic, processing and safety are very different.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:16 pm

uta999 wrote:
Why is the 737-MAX the only aircraft ever to need MCAS? What would a non-MCAS MAX fly like? and could it be any worse than one that has it. Is it simply to mimic the NG in certain flight characteristics? Does it make it safer, easier to fly? Why is removing it completely such an issue? It doesn't work and probably can never be made to work.


The MAX has different aerodynamic characteristics, due to a) larger engine nacelle and b) further forward placing of the engines. As angle of attack increases, the lift generated by the engine nacelles (possibly in combination with Aero interaction between engines, pylon and wing) increases proportionally more than the negative lift generated by the elevator. This results in insufficient natural stability margins in certain parts of the flight envelope. Which results in lighter stick forces at increased angle of attack. The downside of that is that severely increases the risk of entering stall regime.

One way to cope with that would be a to limit the approved flight envelope, but that would have an impact on the operational use of the model. Another way would be to use a system to restore the stability margin. Which is what MCAS does by trimming the stabilizer down.

As a side note, the KC-767 tanker also employs MCAS. And I believe that Concorde also had a sort of stablity enhancing system which is needed as the wide flight envelope upto Mach 2.0 can not be covered through normal aero natural stability.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:18 pm

JetBuddy wrote:
If you've used up your "free" articles, you can sometimes google the title and be able to read it anyway.


delete the cookies for the domain. voila.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:22 pm

Revelation wrote:
kalvado wrote:
Revelation wrote:
3) A non-MCAS MAX would be slightly worse in this scenario, but no one should be near that part of the flight envelope in commercial service

A bit of a side comment:
One may argue that no one should have open flames on board, loss of cabin pressure or water landing in normal operations - yet fire extinguishing, oxygen masks and all flavors of flotation devices are mandatory, and actually get used once in a while.
High-reliability systems - like airplanes, nuclear power plants, medical devices etc - need to account for all sorts of abnormal situations to keep that high-reliability status.

Yes, because open flames breaking out are the same as a few pounds less force on the control stick AFTER stick shaker and horns have been going off for a long time...

Please...

We are talking about basic airmanship here, or the lack of it.

Every pilot gets hard core training about stalling the aircraft and how to not put it into that part of the flight envelope.

If you proceed to do this, and you've ignored the stick shaker and the horns to do so, constant stick force isn't going to help you either.

Yeah, for some reason Boeing keeps calling stability control system "a few pounds of force". Few (thousand) degrees of heat are not that big of a deal as well, if you think about it.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:28 pm

planecane wrote:
First of all, it was an FAA test group, not a Boeing test group.

. . .

My point is not that MCAS 1.0 was an acceptable design. It was not. My point is that when I board an aircraft, I am putting my life in the hands of the two people at the controls and I have an expectation that they are trained well enough and have the skills to save my life any time that the possibility exists to do so.


I was not referring to the FAA test group. The only pilot group continuing to accumulate MAX time is the Boeing test group (they are still doing first flights, further test flights, ferry flights, and development flights).

I don't disagree that airline pilots should be well trained and be expected to handle an emergency. IINM, they have to demonstrate that every 6 months in a hectic sim ride where all sorts of stuff are thrown at them.
I disagree that airline pilots would be some sort of super humans, able to cope with just about everything. That may have bene the case in the sixties and seventies of the previous century. But in today’s environment that is no0t the case. If at all, with growth of the airline sector, the pilots task should become more and more simple. This has been the case with each new design and major derivative (just check out the cockpit of the first generation 737 with the NG). The problem is that MCAS-failure goes heavily against that.

But in any case, if we feel that pilots should be able to handle MCAS going rogue type of event, it would certainly help if we would train them for such an event. Which was not the case. And even after the Lion Air accident, it still was not the case. Yes, pilots were reminded to use existing procedures. But that is not training.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:34 pm

MSPNWA wrote:
Take just the "four seconds" part. It implies that the pilots have only four seconds under a challenging situation to take the correct action to save the plane. We know that implication is highly misleading at best. In reality the pilots had much more time than four seconds to diagnose and counter an MCAS runaway.

And as usual we have a very sensationalist summary of the cockpit situation that avoids key facts such as none of the problems presented to the pilots should be foreign. They should have had knowledge and been trained on each malfunction, even MCAS. But that wouldn't fit the narrative, so relevant facts have to be left out. The picture is painted that nothing could be expected to be done in the cockpit, which is false.

Indeed, this is the same thing the "60 Minutes Australia" MCAS report did.

In that report they jump from the reporter and a pilot in a sim session with the flight rolling down to the runway to MCAS kicking in, with no mention of the stick shaker going off on one side shortly after takeoff and continuing for a few minutes, nor any commentary about what the pilots did or did not do to address that issue.

And again, FAA, Boeing, etc admit the pilots should not have been put into this situation, but that doesn't change the fact that the media is misrepresenting how things actually went down.

WSJ's piece didn't bother to mention Boeing's admission, or FAA's testimony to Congress, because that would be a buzz kill.

Instead, it was as sensational as they could make it, even ending with a lucid description of the aircraft slamming into the ground.

kalvado wrote:
Yeah, for some reason Boeing keeps calling stability control system "a few pounds of force". Few (thousand) degrees of heat are not that big of a deal as well, if you think about it.

A few thousand degrees of heat AFTER you were given a loud fire warning minutes before and did nothing about it, even though the controls for the fire suppression system are in your hand...

Maybe you should go to a smaller airport and see if you can't get someone to give you some stall demonstrations in a small plane, I think you'd have a better idea of what we are talking about.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 1:46 pm

planecane wrote:
It doesn't matter if the emergency happens once in the service life of a model or once a week. The frequency of occurrence shouldn't matter when it comes to pilot's abilities to recover. If MCAS 1.0 had only failed once in the next 30 years of service of the MAX, I would expect the crew of that flight to have been able to recover from it.


Frequency is a very big part in deciding training requirements. It's about risk management. Risk comprises frequency and results. Unfortunately MCAS failed in both aspects: high frequency, and disastrous results. Which is basically why the MAX was, and continues to be grounded: it was so far in the red extreme part of the risk matrix.

And all of that still ignores that the accident crews were facing numerous alarms, warnings. We now know that they should have put MCAS, stabilizer trim at the top of their priority list. Heck, some are blaming the ET crew for allowing the speed to get out of control, when by the first MCAS cycle they were well within Vmo, and trying to recover from stall warning . . .

In any case, I'm undecided if we can leave the "MCAS Back Stop" with cockpit crews (EASA and FAA now seem to disagree), but if so, they need to be trained for that. And they were not. I sincerely disagree that such training would fall in the category "general piloting skills"; it is very type specific to the MAX.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 2:01 pm

Revelation wrote:
MSPNWA wrote:
Take just the "four seconds" part. It implies that the pilots have only four seconds under a challenging situation to take the correct action to save the plane. We know that implication is highly misleading at best. In reality the pilots had much more time than four seconds to diagnose and counter an MCAS runaway.

And as usual we have a very sensationalist summary of the cockpit situation that avoids key facts such as none of the problems presented to the pilots should be foreign. They should have had knowledge and been trained on each malfunction, even MCAS. But that wouldn't fit the narrative, so relevant facts have to be left out. The picture is painted that nothing could be expected to be done in the cockpit, which is false.

Indeed, this is the same thing the "60 Minutes Australia" MCAS report did.

In that report they jump from the reporter and a pilot in a sim session with the flight rolling down to the runway to MCAS kicking in, with no mention of the stick shaker going off on one side shortly after takeoff and continuing for a few minutes, nor any commentary about what the pilots did or did not do to address that issue.

And again, FAA, Boeing, etc admit the pilots should not have been put into this situation, but that doesn't change the fact that the media is misrepresenting how things actually went down.

WSJ's piece didn't bother to mention Boeing's admission, or FAA's testimony to Congress, because that would be a buzz kill.

Instead, it was as sensational as they could make it, even ending with a lucid description of the aircraft slamming into the ground.



To make sure we are talking about the same thing: what exactly are those four seconds standing for? Do we know that? I could not get that from the WSJ article. I tried to read it again, but was blocked the second time.

Thanks.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 2:09 pm

Revelation wrote:
kalvado wrote:
Revelation wrote:
3) A non-MCAS MAX would be slightly worse in this scenario, but no one should be near that part of the flight envelope in commercial service

A bit of a side comment:
One may argue that no one should have open flames on board, loss of cabin pressure or water landing in normal operations - yet fire extinguishing, oxygen masks and all flavors of flotation devices are mandatory, and actually get used once in a while.
High-reliability systems - like airplanes, nuclear power plants, medical devices etc - need to account for all sorts of abnormal situations to keep that high-reliability status.

Yes, because open flames breaking out are the same as a few pounds less force on the control stick AFTER stick shaker and horns have been going off for a long time...

Please...

We are talking about basic airmanship here, or the lack of it.

Every pilot gets hard core training about stalling the aircraft and how to not put it into that part of the flight envelope.

If you proceed to do this, and you've ignored the stick shaker and the horns to do so, constant stick force isn't going to help you either.


The basic airmanship takes into account some fundamental aircraft basics, such as certain stability margins. Once those fundamentals are out the door, then one need to redefine basic airmanship.

Or in other words, the non-MCAS Max could very well be the difference between the minimum competency level of an airline pilot, vs that of test pilot territory.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 2:37 pm

PW100 wrote:
To make sure we are talking about the same thing: what exactly are those four seconds standing for? Do we know that? I could not get that from the WSJ article. I tried to read it again, but was blocked the second time.

https://ih.advfn.com/stock-market/NYSE/ ... doomed-the still works:

In designing the flight controls for the 737 MAX, Boeing assumed that pilots trained on existing safety procedures should be able to sift through the jumble of contradictory warnings and take the proper action 100% of the time within four seconds.

That is about the amount of time that it took you to read this sentence.

Boeing bet nearly everything on those four ticks of the clock. The company's belief in its engineering, and its reliance on pilots to be flawless cogs, enabled Boeing to speed the latest iteration of its most important airliner to market and ultimately saved money for its customers.

Pretty lurid, eh?

I think it refers to the serious vs catastrophic FAA classifications, but the WSJ sexed it up to being a Boeing criteria.

In reality there were sequences of alarms and events leading up to the MCAS activation.

In viewtopic.php?t=1422795#p21365865 I wrote:

My criticism is in the other thread we were told 737 pilots are taught they must not raise the flaps after the stick shaker activates. In this 60 Minutes Australia production at 0:30 they are rolling down the runway and rotate and at 0:50 the video jumps straight to retracting the flaps but does not show any stick shaker and thus no consideration of the pilots reaction to the stick shaker or lack thereof. The video leaves the impression of perfectly normal flight before flaps up, and evidence that this was not the case was not presented.

https://news.aviation-safety.net/2018/1 ... -accident/ gives us the timeline:

Both reports seem to skip a lot of the story to get right to the "4 seconds of terror" sensationalistic hype.

PW100 wrote:
Or in other words, the non-MCAS Max could very well be the difference between the minimum competency level of an airline pilot, vs that of test pilot territory.

I hope you are not suggesting an airman who ignores stick shakers and aural warnings and proceeds to fly towards the onset of stall is a competent airman.

I hope we're not conflating the MCAS 1.0 situation where the bad design/implementation of MCAS put too much workload on the pilots as admitted both by Boeing and FAA, with either the non-MCAS or MCAS 2.0 situations.

In the non-MCAS and MCAS 2.0 situations we don't have all the complications generated by MCAS 1.0 using false data to generate high workload due to false alarms and we don't have the airplane repeatedly pushing the nose down.

I think most of us would agree that by the time MCAS 2.0 is fully tested and certified we should be back to the case where the "minimum competency level of an airline pilot" is sufficient.

Part of that "minimum competency level of an airline pilot" includes correct reaction to stall warnings, IMO.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 2:48 pm

PW100 wrote:
In any case, I'm undecided if we can leave the "MCAS Back Stop" with cockpit crews (EASA and FAA now seem to disagree), but if so, they need to be trained for that. And they were not. I sincerely disagree that such training would fall in the category "general piloting skills"; it is very type specific to the MAX.


With MCAS 2.0 they aren't the back stop anymore. Unless you mean the back stop if MCAS gets disabled and they have to fly without it.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 3:10 pm

Revelation wrote:
I think most of us would agree that by the time MCAS 2.0 is fully tested and certified we should be back to the case where the "minimum competency level of an airline pilot" is sufficient.

Part of that "minimum competency level of an airline pilot" includes correct reaction to stall warnings, IMO.

Including false stall warnings due to a erratic high AoA reading ? We know that the MCAS will be fixed, but will the the stall warning be modified ?
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 3:14 pm

PixelFlight wrote:
Revelation wrote:
I think most of us would agree that by the time MCAS 2.0 is fully tested and certified we should be back to the case where the "minimum competency level of an airline pilot" is sufficient.

Part of that "minimum competency level of an airline pilot" includes correct reaction to stall warnings, IMO.

Including false stall warnings due to a erratic high AoA reading ? We know that the MCAS will be fixed, but will the the stall warning be modified ?

The reason why Peter Lemme was so ecstatic about the "cosmic ray" fix is that it addresses much more than the MCAS problem, including erratic AoA inputs causing the two FCCs to generate different outputs, cosmic rays causing random bit flips, etc.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 3:30 pm

Revelation wrote:
PW100 wrote:
To make sure we are talking about the same thing: what exactly are those four seconds standing for? Do we know that? I could not get that from the WSJ article. I tried to read it again, but was blocked the second time.

https://ih.advfn.com/stock-market/NYSE/ ... doomed-the still works:

In designing the flight controls for the 737 MAX, Boeing assumed that pilots trained on existing safety procedures should be able to sift through the jumble of contradictory warnings and take the proper action 100% of the time within four seconds.

That is about the amount of time that it took you to read this sentence.

Boeing bet nearly everything on those four ticks of the clock. The company's belief in its engineering, and its reliance on pilots to be flawless cogs, enabled Boeing to speed the latest iteration of its most important airliner to market and ultimately saved money for its customers.

Pretty lurid, eh?

I think it refers to the serious vs catastrophic FAA classifications, but the WSJ sexed it up to being a Boeing criteria.


Yes, I got that part. But I can't refer the four seconds back to a specific situation on neither of the accidents.
Since you and MSPNWA were jumping on this, that suggested you understood the importance (or rather lack of . . .) in relation to the accidents. I must have misunderstood.
Last edited by PW100 on Sat Aug 17, 2019 3:45 pm, edited 1 time in total.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 3:44 pm

Revelation wrote:
PW100 wrote:
Or in other words, the non-MCAS Max could very well be the difference between the minimum competency level of an airline pilot, vs that of test pilot territory.

I hope you are not suggesting an airman who ignores stick shakers and aural warnings and proceeds to fly towards the onset of stall is a competent airman.

I hope we're not conflating the MCAS 1.0 situation where the bad design/implementation of MCAS put too much workload on the pilots as admitted both by Boeing and FAA, with either the non-MCAS or MCAS 2.0 situations.

In the non-MCAS and MCAS 2.0 situations we don't have all the complications generated by MCAS 1.0 using false data to generate high workload due to false alarms and we don't have the airplane repeatedly pushing the nose down.

I think most of us would agree that by the time MCAS 2.0 is fully tested and certified we should be back to the case where the "minimum competency level of an airline pilot" is sufficient.

Part of that "minimum competency level of an airline pilot" includes correct reaction to stall warnings, IMO.


The “putting workload on the pilots” referred to the MCAS misbehaviour. I was replying to the poster's (hypothetical) non-MCAS Max situation (never mind 2.0). Workload is not in the picture there.

All stick shakers and aural warnings settings are based on the same basic aircraft fundamentals in terms of natural stability margin. Once those natural stability margins are no longer respected, then any subsequent crew actions cannot be judged. To put it a bit more extreme, what help would stick shakers and aural warnings provide if the aircraft is (very) unstable in pitch? None. They would be too little too late (and again, for the record, I am not claiming that the Max is unstable in pitch).

Are you suggesting that as long as an aircraft has stick shakers and aural warnings, stick force gradient FARs can be tossed out the window? Have you suggested that to FAA and EASA?

The fundamentals of basic airmanship are engraved by the fundamentals of basic aircraft behaviour. And those are guarded by those pesky FAR's like stick force gradient. They are there for a reason, so that things like basic airmanship can be defined and relied upon. Get rid of these FARs, and it becomes impossible to define basic airmanship, let alone to rely on it.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 4:12 pm

Revelation wrote:
I hope you are not suggesting an airman who ignores stick shakers and aural warnings and proceeds to fly towards the onset of stall is a competent airman.

Thinking about it... Did Boeing ever gave an exact value for MCAS threshold, and same for the shaker?
As they said, MCAS is coming up during extreme, but legitimate maneuvers - so I assume shaker should come up not BEFORE, but AFTER MCAS.
If this is true, it throws a lot of "competent pilot" argument out of the window.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019 [OT]

Sat Aug 17, 2019 4:26 pm

cledaybuck wrote:
Do we need apple to bring back the ipod too? :D


iPod is still available.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 5:17 pm

kalvado wrote:
Revelation wrote:
I hope you are not suggesting an airman who ignores stick shakers and aural warnings and proceeds to fly towards the onset of stall is a competent airman.

Thinking about it... Did Boeing ever gave an exact value for MCAS threshold, and same for the shaker?
As they said, MCAS is coming up during extreme, but legitimate maneuvers - so I assume shaker should come up not BEFORE, but AFTER MCAS.
If this is true, it throws a lot of "competent pilot" argument out of the window.


MCAS comes up well after stick shaker.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 5:21 pm

7BOEING7 wrote:
kalvado wrote:
Revelation wrote:
I hope you are not suggesting an airman who ignores stick shakers and aural warnings and proceeds to fly towards the onset of stall is a competent airman.

Thinking about it... Did Boeing ever gave an exact value for MCAS threshold, and same for the shaker?
As they said, MCAS is coming up during extreme, but legitimate maneuvers - so I assume shaker should come up not BEFORE, but AFTER MCAS.
If this is true, it throws a lot of "competent pilot" argument out of the window.


MCAS comes up well after stick shaker.

ANy credible source?
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 5:24 pm

Reposting due to previous error.

PW100 wrote:
Revelation wrote:
I hope you are not suggesting an airman who ignores stick shakers and aural warnings and proceeds to fly towards the onset of stall is a competent airman.
...
Part of that "minimum competency level of an airline pilot" includes correct reaction to stall warnings, IMO.

All stick shakers and aural warnings settings are based on the same basic aircraft fundamentals in terms of natural stability margin. Once those natural stability margins are no longer respected, then any subsequent crew actions cannot be judged. To put it a bit more extreme, what help would stick shakers and aural warnings provide if the aircraft is (very) unstable in pitch? None. They would be too little too late (and again, for the record, I am not claiming that the Max is unstable in pitch).

Are you suggesting that as long as an aircraft has stick shakers and aural warnings, stick force gradient FARs can be tossed out the window? Have you suggested that to FAA and EASA?

The fundamentals of basic airmanship are engraved by the fundamentals of basic aircraft behaviour. And those are guarded by those pesky FAR's like stick force gradient. They are there for a reason, so that things like basic airmanship can be defined and relied upon. Get rid of these FARs, and it becomes impossible to define basic airmanship, let alone to rely on it.

I'm sorry, but IMO you are using reduction to absurdity and strawman arguments by using the specter of an unstable aircraft that you yourself say doesn't exist to avoid addressing a point about the competence of an airman that would ignore stick shakers and aural warnings, then suggesting that acting on the warnings you do get (which go beyond stick shaker and aural warnings) implies favoring the idea of getting rid of FARs related to aircraft stability.

Above I wrote that I think the FAR is a good idea:

Revelation wrote:
A post worth repeating:

planecane wrote:
Without MCAS, the MAX would not have passed the wind-up turn test during certification. Outside of that, if MCAS had just been left out, it is very likely that there never would have been an incident caused by the pitch up tendency during an approach to stall under very specific conditions. Pilots should never get to that point in the flight envelope because there will be all kinds of warnings before they reach that point. Mentour pilot had a great video on youtube showing how difficult it is, even on the antiquated 737 with no envelope protection, to get to the point of stalling. Even when he purposely stalled, it was not difficult to recover.

The idea that stick forces should not lighten as stall approaches is a good idea.

Had MCAS 1.0 been properly engineered we probably never would have known it exists.

This doesn't change the fact that in a non-MCAS MAX there would be plenty of warnings of the onset of a stall well before the high AoA allowed nacelle lift to lighten stick forces to a noticeable degree.

BTW I believe the referenced video is https://www.youtube.com/watch?v=TlinocVHpzk

This video demonstrates that there are a lot more signs of the stall other than aural warnings or stick shakers, we have activation of auto trim, increasing angle of attack, appearance of pitch limit indicators, feeling some amount of physical buffeting, textual buffet alerts, blinking amber speed indicator, then aural warning and stick shaker. All this before you actually stall, and even then, stall recovery is a basic skill. Again, all of this presumes we are in the non-MCAS-1.0 situation.
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sgrow787
Posts: 262
Joined: Fri May 16, 2014 8:12 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sat Aug 17, 2019 5:49 pm

planecane wrote:
ACATROYAL wrote:
It simply comes down to the fact the MAX is a variant gone too far. The engines are the main problem... too big , they throw the center of gravity way off creating all sorts of problems talked about to death in this thread...


The problem isn't the center of gravity being too far forward. MCAS is needed because it has a tendency to pitch up under certain conditions. If the center of gravity being too far forward was an issue, it would cause it to pitch down.

The MAX is perfectly stable and doesn't require MCAS or any other automated system in normal flight. It is only under very specific conditions that do not occur during typical operations where the pitch up tendency occurs.

Without MCAS, the MAX would not have passed the wind-up turn test during certification. Outside of that, if MCAS had just been left out, it is very likely that there never would have been an incident caused by the pitch up tendency during an approach to stall under very specific conditions. Pilots should never get to that point in the flight envelope because there will be all kinds of warnings before they reach that point. Mentour pilot had a great video on youtube showing how difficult it is, even on the antiquated 737 with no envelope protection, to get to the point of stalling. Even when he purposely stalled, it was not difficult to recover.


Then it makes the point stronger that Boeing must have attempted a two (AOA) sensor design (lets call it MCAS v0.1, where v0.0 was the initial G + AOA design) for a system that needed to work 100% of the time WHEN IT WAS NEEDED, and not misfire 100% of the time when it wasn't needed.

This isnt mere engineering misjudgement. They more likely realized the entire FCC architecture was insufficient to handle redundancy onside + crosside data. And instead of spending another year in development they convinced themselves to meet their market deadline, put the flying public at risk, while keeping the mention of MCAS out of the FCOM to buy time while they continued development.

Just one sensor.
Last edited by sgrow787 on Sat Aug 17, 2019 6:08 pm, edited 1 time in total.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.

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