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On 6/2/19 9:18 AM, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
"Safety analysts said they would have acted differently if they had
known it used just one sensor. Regulators didnât conduct a formal safety
assessment of the new version of MCAS."
IOW the safety analysts and regulators didn't have any idea how the
plane's flight controls actually worked. and most or all of the
employees they were talking to in the course of their duties as analysis
didn't have any idea, either.
That sounds about right. Let the FNG deal with those people
"In regulatory-speak, it meant that MCAS could trigger erroneously less
often than once in 10 million flight hours."
sounds like a management-dictated reliability estimate, a la Space
Shuttle NASA-management dictated reliability estimates of 1 catastrophic
accident per every 10 or 100 thousand flights and not 1 in 50 or 100 as
was more realistic.
10 million flight hours isn't all that much in the grand scheme of
things either given how many planes and flight hours there are intended
to be, if they erroneously downgraded what was actually a "catastrophic"
fault condition to "hazardous" even if the ~10 million hour figure is
correct for a plane like the Max it probably means a guaranteed crash
every 7-8 years or something.
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
--
Thanks,
- Win
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
On Sunday, June 2, 2019 at 9:59:01 AM UTC-4, bitrex wrote:
On 6/2/19 9:18 AM, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
"Safety analysts said they would have acted differently if they had
known it used just one sensor. Regulators didnât conduct a formal safety
assessment of the new version of MCAS."
IOW the safety analysts and regulators didn't have any idea how the
plane's flight controls actually worked. and most or all of the
employees they were talking to in the course of their duties as analysis
didn't have any idea, either.
That sounds about right. Let the FNG deal with those people
"In regulatory-speak, it meant that MCAS could trigger erroneously less
often than once in 10 million flight hours."
sounds like a management-dictated reliability estimate, a la Space
Shuttle NASA-management dictated reliability estimates of 1 catastrophic
accident per every 10 or 100 thousand flights and not 1 in 50 or 100 as
was more realistic.
10 million flight hours isn't all that much in the grand scheme of
things either given how many planes and flight hours there are intended
to be, if they erroneously downgraded what was actually a "catastrophic"
fault condition to "hazardous" even if the ~10 million hour figure is
correct for a plane like the Max it probably means a guaranteed crash
every 7-8 years or something.
The classification as hazardous made the assumption that pilots were
competent and able to identify and deal with what manifests itself as a
runaway trim condition. All pilots are trained on that, yet we had at
least 4 out of 7 that couldn't identify it and follow the procedure.
On 6/2/19 10:26 AM, trader4@optonline.net wrote:
A lot here sounds very wrong at Boeing, in their definitions, in their
probability calculations, in their assumptions. And it could very well
extend to planes beyond the Max, probably to all Boeing planes. I said
before that I will be confident that Boeing has this fixed, but seeing
what went on here, I no longer have the same faith I did in all Boeing
planes.
It sounds like par for the course at say a very top-heavy organization
On Sunday, June 2, 2019 at 9:59:01 AM UTC-4, bitrex wrote:
On 6/2/19 9:18 AM, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
"Safety analysts said they would have acted differently if they had
known it used just one sensor. Regulators didnât conduct a formal safety
assessment of the new version of MCAS."
IOW the safety analysts and regulators didn't have any idea how the
plane's flight controls actually worked. and most or all of the
employees they were talking to in the course of their duties as analysis
didn't have any idea, either.
That sounds about right. Let the FNG deal with those people
"In regulatory-speak, it meant that MCAS could trigger erroneously less
often than once in 10 million flight hours."
sounds like a management-dictated reliability estimate, a la Space
Shuttle NASA-management dictated reliability estimates of 1 catastrophic
accident per every 10 or 100 thousand flights and not 1 in 50 or 100 as
was more realistic.
I don't think that is the estimate, that is the requirement to be considered safe enough given the severity of impact.
10 million flight hours isn't all that much in the grand scheme of
things either given how many planes and flight hours there are intended
to be, if they erroneously downgraded what was actually a "catastrophic"
fault condition to "hazardous" even if the ~10 million hour figure is
correct for a plane like the Max it probably means a guaranteed crash
every 7-8 years or something.
I believe the 10 million flight hours is how often the MCAS would muck up, but not necessarily it would cause an accident or cause injuries. That's the point. If it were considered "catastrophic" meaning the impact were higher, 10 million hours would not be enough.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
It sounds like par for the course at say a very top-heavy organizationA lot here sounds very wrong at Boeing, in their definitions, in their
probability calculations, in their assumptions. And it could very well
extend to planes beyond the Max, probably to all Boeing planes. I said
before that I will be confident that Boeing has this fixed, but seeing
what went on here, I no longer have the same faith I did in all Boeing
planes.
On 6/2/19 9:18 AM, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
"Safety analysts said they would have acted differently if they had
known it used just one sensor. Regulators didnât conduct a formal safety
assessment of the new version of MCAS."
IOW the safety analysts and regulators didn't have any idea how the
plane's flight controls actually worked. and most or all of the
employees they were talking to in the course of their duties as analysis
didn't have any idea, either.
That sounds about right. Let the FNG deal with those people
"In regulatory-speak, it meant that MCAS could trigger erroneously less
often than once in 10 million flight hours."
sounds like a management-dictated reliability estimate, a la Space
Shuttle NASA-management dictated reliability estimates of 1 catastrophic
accident per every 10 or 100 thousand flights and not 1 in 50 or 100 as
was more realistic.
10 million flight hours isn't all that much in the grand scheme of
things either given how many planes and flight hours there are intended
to be, if they erroneously downgraded what was actually a "catastrophic"
fault condition to "hazardous" even if the ~10 million hour figure is
correct for a plane like the Max it probably means a guaranteed crash
every 7-8 years or something.
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
--
Thanks,
- Win
On Sunday, June 2, 2019 at 7:55:36 PM UTC-4, bitrex wrote:
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average every 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 of a Thai Airways jet exploded on the ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737 MAX. They in fact handed the entire certification off to Boeing with the certification reports being "reviewed" by semi-comatose swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread catastrophic 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 just two sensors. The only good a second sensor would serve is if it was something the pilot could switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their pilots.
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
The idea to two seems to be that if they disagree by a substantial amount, then
MCAS will take no action, because something is wrong and the cure is
potentially far worse than the problem.
On 6/2/19 8:15 PM, trader4@optonline.net wrote:
On Sunday, June 2, 2019 at 7:55:36 PM UTC-4, bitrex wrote:
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
  and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
  The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average
every 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 of a Thai Airways jet exploded on the
ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money
on their in-flight entertainment system than a fuel tank oxygen
removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their
interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737
MAX. They in fact handed the entire certification off to Boeing with
the certification reports being "reviewed" by semi-comatose swivel
chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread
catastrophic 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 just two sensors. The only good a
second sensor would serve is if it was something the pilot could
switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their
pilots.
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
The idea to two seems to be that if they disagree by a substantial
amount, then
MCAS will take no action, because something is wrong and the cure is
potentially far worse than the problem.
That makes sense. you can have a "voting system" such as it is with two
sensors but it can't actually _do_ anything other than to take itself
offline and provide a gripe signal that its internal state is inconsistent.
The Space Shuttle had four main computers in a voting system, and IIRC
the plan was if there was a time when there was a repeated two-two split
on some decision of importance then all four would be taken offline and
a fifth normally out-of-the-loop computer would be brought online, which
was hardcoded with only what was necessary for de-orbit and landing, and
return home immediately. Also IIRC there was never a two-two split on
anything during operation of the Shuttle.
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average every 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 of a Thai Airways jet exploded on the ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737 MAX. They in fact handed the entire certification off to Boeing with the certification reports being "reviewed" by semi-comatose swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread catastrophic 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 just two sensors. The only good a second sensor would serve is if it was something the pilot could switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their pilots..
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average every 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 of a Thai Airways jet exploded on the ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737 MAX. They in fact handed the entire certification off to Boeing with the certification reports being "reviewed" by semi-comatose swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread catastrophic 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 just two sensors. The only good a second sensor would serve is if it was something the pilot could switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their pilots..
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average every 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 of a Thai Airways jet exploded on the ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737 MAX. They in fact handed the entire certification off to Boeing with the certification reports being "reviewed" by semi-comatose swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread catastrophic 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 just two sensors. The only good a second sensor would serve is if it was something the pilot could switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their pilots.
On 6/2/19 9:20 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 8:15:39 PM UTC-4, tra...@optonline.net wrote:
On Sunday, June 2, 2019 at 7:55:36 PM UTC-4, bitrex wrote:
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
  and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
  The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average
every 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 of a Thai Airways jet exploded on the
ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more
money on their in-flight entertainment system than a fuel tank
oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual
their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737
MAX. They in fact handed the entire certification off to Boeing
with the certification reports being "reviewed" by semi-comatose
swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread
catastrophic 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 just two sensors. The only
good a second sensor would serve is if it was something the pilot
could switch in when/if the first sensor gave him trouble with the
MCAS.
The fault lies with the airlines for not properly training their
pilots.
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
The idea to two seems to be that if they disagree by a substantial
amount, then
MCAS will take no action, because something is wrong and the cure is
potentially far worse than the problem.
That's the least reliable option because you lose MCAS if either/or
the angle sensors fail. Maybe they think it's important to have MCAS,
making the switchable option the most reliable to that end.
In both crashes the sensor activated MCAS because it thought the angle
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 easily 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 any wiggle room when he's coming in for a landing.
It only takes a few seconds of bad control to put the aircraft in a
bad spot it can't get out of. Maybe they should just shut the damn
thing off below a certain ground height and ground speed.
The way the article framed it was that there was feature-creep in the
design of the MCAS system. from an emergency system that would only
engage in exceptional circumstances to being just another part of the
normal flight controls that was always operating in the background to
make it a more comfortable aircraft to fly.
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average every 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 of a Thai Airways jet exploded on the ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737 MAX. They in fact handed the entire certification off to Boeing with the certification reports being "reviewed" by semi-comatose swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread catastrophic 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 just two sensors. The only good a second sensor would serve is if it was something the pilot could switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their pilots..
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
On Sunday, June 2, 2019 at 8:15:39 PM UTC-4, tra...@optonline.net wrote:
On Sunday, June 2, 2019 at 7:55:36 PM UTC-4, bitrex wrote:
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average every 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 of a Thai Airways jet exploded on the ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737 MAX. They in fact handed the entire certification off to Boeing with the certification reports being "reviewed" by semi-comatose swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread catastrophic 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 just two sensors. The only good a second sensor would serve is if it was something the pilot could switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their pilots.
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
The idea to two seems to be that if they disagree by a substantial amount, then
MCAS will take no action, because something is wrong and the cure is
potentially far worse than the problem.
That's the least reliable option because you lose MCAS if either/or the angle sensors fail. Maybe they think it's important to have MCAS, making the switchable option the most reliable to that end.
In both crashes the sensor activated MCAS because it thought the angle 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 easily 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 any wiggle room when he's coming in for a landing. It only takes a few seconds of bad control to put the aircraft in a bad spot it can't get out of. Maybe they should just shut the damn thing off below a certain ground height and ground speed.
mandag den 3. juni 2019 kl. 01.55.36 UTC+2 skrev bitrex:
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average every 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 of a Thai Airways jet exploded on the ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737 MAX.. They in fact handed the entire certification off to Boeing with the certification reports being "reviewed" by semi-comatose swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread catastrophic 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 just two sensors. The only good a second sensor would serve is if it was something the pilot could switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their pilots.
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
switching it off if the AoAs disagree and reducing the maximum trim it can
do when it is working, would fix the problem of it crashing the plane
but it does pose the question, if it isn't a problem turning it off or
reducing its power why was added in the first place
On Sunday, June 2, 2019 at 7:55:36 PM UTC-4, bitrex wrote:
On 6/2/19 4:37 PM, bloggs.fredbloggs.fred@gmail.com wrote:
On Sunday, June 2, 2019 at 9:18:59 AM UTC-4, Winfield Hill wrote:
Details of an error in engineering procedures
and decision-making:
https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html
The comments to the article are also interesting.
The airlines have a history of this kind of risk taking.
"According to the NTSB, a fuel tank explosion happens on average every 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 of a Thai Airways jet exploded on the ground, killing one person."
http://www.cnn.com/2006/US/07/14/twa.main/index.html
Up to the TWA flight 800 disaster, they were spending way more money on their in-flight entertainment system than a fuel tank oxygen removal system could ever cost.
As for the NYT article, they have the basic facts but as usual their interpretation is pathetically naive.
The FAA is incapable of certifying a design as complex as the 737 MAX.. They in fact handed the entire certification off to Boeing with the certification reports being "reviewed" by semi-comatose swivel chair operators with 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 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.
I agree with Boeing about the MCAS not being a single-thread catastrophic 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 just two sensors. The only good a second sensor would serve is if it was something the pilot could switch in when/if the first sensor gave him trouble with the MCAS.
The fault lies with the airlines for not properly training their pilots.
Has anyone told Boeing there's no point to using two sensors? Cuz as
part of their fix to this issue, according to the article, using two
sensors continually seems to be central to the plan, not just a second
sensor that's switchable/optional.
The idea to two seems to be that if they disagree by a substantial amount, then
MCAS will take no action, because something is wrong and the cure is
potentially far worse than the problem.