OT: Deadly 'Misguided Assumptions' Were Built Into Boeing's 737 Max

four and a half years. In May 1990, six years before TWA 800, a center tank exploded on a Philippine Airlines 737 shortly before take off, killing eig ht people. Four years and eight months after TWA 800, the center tank of a Thai Airways jet exploded on the ground, killing one person."

their in-flight entertainment system than a fuel tank oxygen removal syste m could ever cost.

terpretation is pathetically naive.

They in fact handed the entire certification off to Boeing with the certifi cation reports being "reviewed" by semi-comatose swivel chair operators wit h probably less than 10% (on the high end) comprehension of what they were reading. And when NYT reports Boeing delivered this or that information to FAA, it only means it was part of a probably huge documentation package mos t of which was simply glossed over by the FAA. As is typical of most politi cized bureaucracies, they're just not going to pay much attention to anythi ng that's not already a high visibility issue.

ic failure mechanism because the pilot is always available to pull the syst em out of MCAS control, and the MCAS was relatively slow acting, taking 10 seconds to do anything. And you can't implement a voting scheme with just t wo sensors. The only good a second sensor would serve is if it was somethin g the pilot could switch in when/if the first sensor gave him trouble with the MCAS.

.

Two sensors is just a way of shutting it off if any part of it is not worki ng, cuts the pilot out of the loop. So what happens is you have the pilot, who's banking on MCAS for a successful landing, crashes the aircraft with a bad approach angle. This is what happened to certain crew, whose nationali ty will not be named, that crashed into the pier at San Francisco when they took the ILS offline for a few minutes.

Reply to
bloggs.fredbloggs.fred
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That is to say it might be expected it would also be operating at low ground height/ground speed because it was operating in the other regimes, also. Shut it down in that area and suddenly you're flying a different plane. Which could also be pretty hazardous if you're not expecting it.

Reply to
bitrex

:

ml

ry four and a half years. In May 1990, six years before TWA 800, a center t ank exploded on a Philippine Airlines 737 shortly before take off, killing eight people. Four years and eight months after TWA 800, the center tank of a Thai Airways jet exploded on the ground, killing one person."

on their in-flight entertainment system than a fuel tank oxygen removal sy stem could ever cost.

interpretation is pathetically naive.

X. They in fact handed the entire certification off to Boeing with the cert ification reports being "reviewed" by semi-comatose swivel chair operators with probably less than 10% (on the high end) comprehension of what they we re reading. And when NYT reports Boeing delivered this or that information to FAA, it only means it was part of a probably huge documentation package most of which was simply glossed over by the FAA. As is typical of most pol iticized bureaucracies, they're just not going to pay much attention to any thing that's not already a high visibility issue.

ophic failure mechanism because the pilot is always available to pull the s ystem out of MCAS control, and the MCAS was relatively slow acting, taking

10 seconds to do anything. And you can't implement a voting scheme with jus t two sensors. The only good a second sensor would serve is if it was somet hing the pilot could switch in when/if the first sensor gave him trouble wi th the MCAS.

ots.

d

unt, then

angle sensors fail. Maybe they think it's important to have MCAS, making t he switchable option the most reliable to that end.

was too high and the aircraft was in danger of stalling. So it put the nose down at a steep angle causing the crash. I don't know why it just as easil y could have sensed the nose was down too much and put the nose up causing the plane to stall and crash. The basic problem is the pilot doesn't have a ny wiggle room when he's coming in for a landing. It only takes a few secon ds of bad control to put the aircraft in a bad spot it can't get out of. Ma ybe they should just shut the damn thing off below a certain ground height and ground speed.

Right, and it's a good feature. Boeing failed to properly account for the h uman factor in their failure modes effects analysis.

Reply to
bloggs.fredbloggs.fred

A consequence of having too many software jockeys and not enough pilots on the development team, perhaps. Or not talking to working pilots often enough. Or not really listening to what they had to say.

Reply to
bitrex

How about an MCAS unreliable warning? Of course trained pilots would help, too.

Reply to
krw

Can someone explain what this means?

"Moreover the stall warning in normal law was not possible. However, the stall warning function was still available, and was triggered during the last phase of the flight."

The stall warning was not "possible", but it was "available"???

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Rick C

rote:

tml

ery four and a half years. In May 1990, six years before TWA 800, a center tank exploded on a Philippine Airlines 737 shortly before take off, killing eight people. Four years and eight months after TWA 800, the center tank o f a Thai Airways jet exploded on the ground, killing one person."

y on their in-flight entertainment system than a fuel tank oxygen removal s ystem could ever cost.

r interpretation is pathetically naive.

AX. They in fact handed the entire certification off to Boeing with the cer tification reports being "reviewed" by semi-comatose swivel chair operators with probably less than 10% (on the high end) comprehension of what they w ere reading. And when NYT reports Boeing delivered this or that information to FAA, it only means it was part of a probably huge documentation package most of which was simply glossed over by the FAA. As is typical of most po liticized bureaucracies, they're just not going to pay much attention to an ything that's not already a high visibility issue.

rophic failure mechanism because the pilot is always available to pull the system out of MCAS control, and the MCAS was relatively slow acting, taking 10 seconds to do anything. And you can't implement a voting scheme with ju st two sensors. The only good a second sensor would serve is if it was some thing the pilot could switch in when/if the first sensor gave him trouble w ith the MCAS.

lots.

d

can

producing too much acceleration for the comfort of the passengers, making i t seem like the pilot was fighting for control and it was miracle they land ed in one piece.

Where on earth did that come from?

Reply to
trader4

On Sunday, June 2, 2019 at 8:11:17 PM UTC-4, Lasse Langwadt Christensen wro te:

l

y four and a half years. In May 1990, six years before TWA 800, a center ta nk exploded on a Philippine Airlines 737 shortly before take off, killing e ight people. Four years and eight months after TWA 800, the center tank of a Thai Airways jet exploded on the ground, killing one person."

on their in-flight entertainment system than a fuel tank oxygen removal sys tem could ever cost.

interpretation is pathetically naive.

. They in fact handed the entire certification off to Boeing with the certi fication reports being "reviewed" by semi-comatose swivel chair operators w ith probably less than 10% (on the high end) comprehension of what they wer e reading. And when NYT reports Boeing delivered this or that information t o FAA, it only means it was part of a probably huge documentation package m ost of which was simply glossed over by the FAA. As is typical of most poli ticized bureaucracies, they're just not going to pay much attention to anyt hing that's not already a high visibility issue.

phic failure mechanism because the pilot is always available to pull the sy stem out of MCAS control, and the MCAS was relatively slow acting, taking 1

0 seconds to do anything. And you can't implement a voting scheme with just two sensors. The only good a second sensor would serve is if it was someth ing the pilot could switch in when/if the first sensor gave him trouble wit h the MCAS.

ts.

n

It is a problem at high angles of attack. And regardless of if pilots coul d deal with an approaching stall like that without it, whether it could have been certified without it, the fact remains that the MAx behaves differentl y at that point than other 737s and that was unacceptable. They wanted it to behave the same, so there was no additional training, or worse, a different type rating being needed.

Reply to
trader4

l

y four and a half years. In May 1990, six years before TWA 800, a center ta nk exploded on a Philippine Airlines 737 shortly before take off, killing e ight people. Four years and eight months after TWA 800, the center tank of a Thai Airways jet exploded on the ground, killing one person."

on their in-flight entertainment system than a fuel tank oxygen removal sys tem could ever cost.

interpretation is pathetically naive.

. They in fact handed the entire certification off to Boeing with the certi fication reports being "reviewed" by semi-comatose swivel chair operators w ith probably less than 10% (on the high end) comprehension of what they wer e reading. And when NYT reports Boeing delivered this or that information t o FAA, it only means it was part of a probably huge documentation package m ost of which was simply glossed over by the FAA. As is typical of most poli ticized bureaucracies, they're just not going to pay much attention to anyt hing that's not already a high visibility issue.

phic failure mechanism because the pilot is always available to pull the sy stem out of MCAS control, and the MCAS was relatively slow acting, taking 1

0 seconds to do anything. And you can't implement a voting scheme with just two sensors. The only good a second sensor would serve is if it was someth ing the pilot could switch in when/if the first sensor gave him trouble wit h the MCAS.

ts.

king, cuts the pilot out of the loop. So what happens is you have the pilot , who's banking on MCAS for a successful landing, crashes the aircraft with a bad approach angle. This is what happened to certain crew, whose nationa lity will not be named, that crashed into the pier at San Francisco when th ey took the ILS offline for a few minutes.

MCAS has nothing to do with approach angle or landing. It only activates a t extreme, high angles of attack, where the plane is close to stalling. And MCAS is deactivated anytime flaps are deployed. It has nothing to do with a successful landing.

Reply to
trader4

e:

tml

nd

Two things. First you also needed a dangerous angle of attack, nearing a stall, which the plane would not see during normal operations. Second at lower speeds and elevation, eg landing, as soon as flaps are activated, MCAS is disabled.

Reply to
trader4

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very four and a half years. In May 1990, six years before TWA 800, a center tank exploded on a Philippine Airlines 737 shortly before take off, killin g eight people. Four years and eight months after TWA 800, the center tank of a Thai Airways jet exploded on the ground, killing one person."

ey on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.

ir interpretation is pathetically naive.

MAX. They in fact handed the entire certification off to Boeing with the ce rtification reports being "reviewed" by semi-comatose swivel chair operator s with probably less than 10% (on the high end) comprehension of what they were reading. And when NYT reports Boeing delivered this or that informatio n to FAA, it only means it was part of a probably huge documentation packag e most of which was simply glossed over by the FAA. As is typical of most p oliticized bureaucracies, they're just not going to pay much attention to a nything that's not already a high visibility issue.

trophic failure mechanism because the pilot is always available to pull the system out of MCAS control, and the MCAS was relatively slow acting, takin g 10 seconds to do anything. And you can't implement a voting scheme with j ust two sensors. The only good a second sensor would serve is if it was som ething the pilot could switch in when/if the first sensor gave him trouble with the MCAS.

ilots.

nd

unt, then

angle sensors fail. Maybe they think it's important to have MCAS, making th e switchable option the most reliable to that end.

as too high and the aircraft was in danger of stalling. So it put the nose down at a steep angle causing the crash. I don't know why it just as easily could have sensed the nose was down too much and put the nose up causing t he plane to stall and crash. The basic problem is the pilot doesn't have an y wiggle room when he's coming in for a landing. It only takes a few second s of bad control to put the aircraft in a bad spot it can't get out of. May be they should just shut the damn thing off below a certain ground height a nd ground speed.

They had that as an "option" and even if you ordered it, it didn't work! Boeing offered an AOA disagree light and an AOA display as options. They learned in 2017 that the planes that had the disagree light, it never worked because of a software error. They were planning on fixing it someday, but in the meantime never told operators about the disagree light not working. It probably wouldn't have made a difference anyway as the pilots in the crashes were overwhelmed and couldn't identify a runaway trim situation and deal with it. And I don't think the crash planes had the disagree option either.

Reply to
trader4

:

ml

ry four and a half years. In May 1990, six years before TWA 800, a center t ank exploded on a Philippine Airlines 737 shortly before take off, killing eight people. Four years and eight months after TWA 800, the center tank of a Thai Airways jet exploded on the ground, killing one person."

on their in-flight entertainment system than a fuel tank oxygen removal sy stem could ever cost.

interpretation is pathetically naive.

X. They in fact handed the entire certification off to Boeing with the cert ification reports being "reviewed" by semi-comatose swivel chair operators with probably less than 10% (on the high end) comprehension of what they we re reading. And when NYT reports Boeing delivered this or that information to FAA, it only means it was part of a probably huge documentation package most of which was simply glossed over by the FAA. As is typical of most pol iticized bureaucracies, they're just not going to pay much attention to any thing that's not already a high visibility issue.

ophic failure mechanism because the pilot is always available to pull the s ystem out of MCAS control, and the MCAS was relatively slow acting, taking

10 seconds to do anything. And you can't implement a voting scheme with jus t two sensors. The only good a second sensor would serve is if it was somet hing the pilot could switch in when/if the first sensor gave him trouble wi th the MCAS.

ots.

d

unt, then

angle sensors fail. Maybe they think it's important to have MCAS, making t he switchable option the most reliable to that end.

was too high and the aircraft was in danger of stalling. So it put the nose down at a steep angle causing the crash. I don't know why it just as easil y could have sensed the nose was down too much and put the nose up causing the plane to stall and crash. The basic problem is the pilot doesn't have a ny wiggle room when he's coming in for a landing. It only takes a few secon ds of bad control to put the aircraft in a bad spot it can't get out of. Ma ybe they should just shut the damn thing off below a certain ground height and ground speed.

They didn't actually say that. What they said was that MCAS was later extended to lower speeds too. But you still needed a dangerous angle of attack, approaching a stall, which the aircraft would not see during normal operation.

Reply to
trader4

I believe he is talking about why the MCAS was added in the first place, to improve the handling characteristics.

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Reply to
Rick C

ote:

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I'm not certain, but I don't think the MCAS was installed to deal with impe nding stalls. It was added to improve the handling characteristics of the plane. To make it feel like other 737s since the new engines altered that characteristic. I haven't read anywhere that the new engines would cause t he plane to stall.

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Reply to
Rick C

Aircraft regularly encounter "non-normal" conditions. of course.

Windshear is a classic extreme example, but there are others.

Reply to
Tom Gardner

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pending stalls. It was added to improve the handling characteristics of th e plane.

Well, you're wrong. MCAS was added specifically to counter the tendency of the Max to increase nose up when approaching a stall because of the placement of the new, larger engines.

To make it feel like other 737s since the new engines altered that charact eristic. I haven't read anywhere that the new engines would cause the plan e to stall.

The engines don't cause the stall, but if the plane gets into an unusual event where the angle of attack is approaching a stall, the size and placement of the new engines will push the nose up even more. And that was not only undesirable, but also different from how the existing 737 fleet behaves.

Reply to
trader4

Like I said, where on earth did that come from? If it's what you say, it makes no sense. MCAS has nothing to do with passenger comfort or landing approaches.

Reply to
trader4

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impending stalls. It was added to improve the handling characteristics of the plane.

MCAS is not an anti stall system, 737 pilots have repeated that numerous ti mes

MCAS is there to make a 737-Max behave like a 737-NG

Reply to
Lasse Langwadt Christensen

On Monday, June 3, 2019 at 1:56:19 PM UTC-4, Lasse Langwadt Christensen wro te:

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It most certainly is an anti-stall system. The Max when pushed to a high level of attack will tend to push itself further nose up into a stall. It's both an anti-stall system and to make the Max behave like other 737s that don't exhibit that undesirable behavior. And also possibly because they could not get it certified without it too.

Reply to
trader4

e:

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every four and a half years. In May 1990, six years before TWA 800, a cente r tank exploded on a Philippine Airlines 737 shortly before take off, killi ng eight people. Four years and eight months after TWA 800, the center tank of a Thai Airways jet exploded on the ground, killing one person."

ney on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.

eir interpretation is pathetically naive.

MAX. They in fact handed the entire certification off to Boeing with the c ertification reports being "reviewed" by semi-comatose swivel chair operato rs with probably less than 10% (on the high end) comprehension of what they were reading. And when NYT reports Boeing delivered this or that informati on to FAA, it only means it was part of a probably huge documentation packa ge most of which was simply glossed over by the FAA. As is typical of most politicized bureaucracies, they're just not going to pay much attention to anything that's not already a high visibility issue.

strophic failure mechanism because the pilot is always available to pull th e system out of MCAS control, and the MCAS was relatively slow acting, taki ng 10 seconds to do anything. And you can't implement a voting scheme with just two sensors. The only good a second sensor would serve is if it was so mething the pilot could switch in when/if the first sensor gave him trouble with the MCAS.

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e producing too much acceleration for the comfort of the passengers, making it seem like the pilot was fighting for control and it was miracle they la nded in one piece.

That info is from the second set of Boeing test pilots who described the fl ight characteristics as "too rough" for passenger comfort. So they modified the original MCAS to the current form. The original MCAS included a g-thre shold in addition to attack angle. I think that one had to do with survivin g turbulence like microbursts.

Reply to
bloggs.fredbloggs.fred

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