737-Max 8 safety concerns
#196
Join Date: Dec 2001
Location: China
Posts: 1,538
There's the romantic view that flying bugsmashers around for a few hundred hours on a wide range of aircraft allows people to 'see the elephant' and do 'real flying' before they get into a real plane - but I am not sure of any real evidence that that is better than an airline internal apprentice system
#197
FlyerTalk Evangelist
Join Date: Nov 2009
Location: SEA (the REAL Washington); occasionally in the other Washington (DCA area)
Programs: DL PM 1.57MM; AS MVPG 100K
Posts: 21,304
... As to the 'blame the pilots' - they were certified & trained as per Boeing/ ICAO standards, and in both cases, sure, someone absolutely on the ball, and aware of all the issues, making the right decisions could have saved the aircraft. But Sully failed as well from that POV (pilots in the simulator could land his aircraft safely back, rather than ditching) ...
#198
FlyerTalk Evangelist
Join Date: Nov 2004
Location: Melbourne
Programs: ►QFWP/LTG►VA WP►HyattExpl.►HiltonGold►ALL Silver
Posts: 21,990
I work in IT myself and find this article very interesting:
How the Boeing 737 Max Disaster Looks to a Software Developer - IEEE Spectrum
How the Boeing 737 Max Disaster Looks to a Software Developer - IEEE Spectrum
#199
A FlyerTalk Posting Legend
Join Date: Feb 2000
Location: Cambridge
Posts: 63,555
This part of the article published in IEEE Spectrum's site (not their official view) is pretty much my viewpoint
(bolding mine)
MCAS software design violates the fundamental principles of quality automated monitoring/response software.
If there were two separate flight computers each with access to (in theory) identical sensor data, then a basic principle says that MCAS should NOT be permitted to take any action without agreement between both computers. Boeing didn't include that basic precaution.
That's why I think Boeing bears the primary responsibility for 350+ people being dead.
Finally, the software relied on systems known for their propensity to fail (angle-of-attack indicators) and did not appear to include even rudimentary provisions to cross-check the outputs of the angle-of-attack sensor against other sensors, or even the other angle-of-attack sensor. Big strike No. 3.
...
Another difference is between the autopilots in my system and that in the 737 Max. All of the CAN businterconnected components constantly do the kind of instrument cross-check that human pilots do and that, apparently, the MCAS system in the 737 Max does not.
...
Another difference is between the autopilots in my system and that in the 737 Max. All of the CAN businterconnected components constantly do the kind of instrument cross-check that human pilots do and that, apparently, the MCAS system in the 737 Max does not.
MCAS software design violates the fundamental principles of quality automated monitoring/response software.
If there were two separate flight computers each with access to (in theory) identical sensor data, then a basic principle says that MCAS should NOT be permitted to take any action without agreement between both computers. Boeing didn't include that basic precaution.
That's why I think Boeing bears the primary responsibility for 350+ people being dead.
#200
FlyerTalk Evangelist
Join Date: Nov 2005
Location: Phoenix, AZ
Programs: AA Gold AAdvantage Elite, Rapids Reward
Posts: 38,293
#201
Join Date: May 2009
Location: South Park, CO
Programs: Tegridy Elite
Posts: 5,678
https://www.businessinsider.com/boei...ussions-2019-4
Twice there were discussions within the FAA about grounding the WN fleet and requiring additional MAX training, in connection with this feature.
Southwest Airlines and the Federal Aviation Administration (FAA) officials who monitor the carrier were unaware that a standard safety feature, designed to warn pilots about malfunctioning sensors, on Boeing 737 Max jets was turned off when Southwest began flying the model in 2017, reported Andy Pastzor of the Wall Street Journal.
In earlier 737 models, the safety feature alerted pilots when a sensor called the "angle-of-attack vane" incorrectly conveyed the pitch of the plane's nose, according to Pastzor. In the Max, it functions as such while also signaling when the Maneuvering Characteristics Augmentation System (MCAS) — a new automated system linked to both October's Lion Air crash and March's Ethiopian Airlines crash — could misfire; but these alerts were only enabled if carriers purchased additional safety features, Pastzor wrote.
In earlier 737 models, the safety feature alerted pilots when a sensor called the "angle-of-attack vane" incorrectly conveyed the pitch of the plane's nose, according to Pastzor. In the Max, it functions as such while also signaling when the Maneuvering Characteristics Augmentation System (MCAS) — a new automated system linked to both October's Lion Air crash and March's Ethiopian Airlines crash — could misfire; but these alerts were only enabled if carriers purchased additional safety features, Pastzor wrote.
#202
Join Date: Nov 2005
Location: on the path to perdition
Programs: Delta, United
Posts: 4,777
I have not read the whole thread but this article should be of interest:
https://spectrum.ieee.org/aerospace/...ware-developer
https://spectrum.ieee.org/aerospace/...ware-developer
#203
Join Date: Jul 2013
Location: Dubai
Posts: 3,301
Boeing Co. on Monday said certain safety alerts on its 737 MAX jets didn’t operate as airlines would have anticipated because of a previously undisclosed error on its part.
#204
Join Date: May 2009
Location: South Park, CO
Programs: Tegridy Elite
Posts: 5,678
Boeing relied on single sensor for 737 Max that had been flagged 216 times to FAA
In addition to not including inputs from two AOA sensors in its original design, Boeing did not flight test AOA sensor malfunctions and how MCAS software would respond, according to several sources.
A former Boeing pilot who tested the 737 Max, who requested anonymity due to fears of negative repercussions, told CNN "I don't think we appreciated the ramifications of a... failure of an AOA probe."
Another source familiar with the 737 MAX testing said the failure of an AOA sensor was not flight tested, but rather "analyzed in the design and certification" of the aircraft, and it was determined trained pilots would have been able to handle the failure.
A second former Boeing test pilot was surprised to learn that the company had relied on a single sensor, as opposed to a redundant system, to perform such a vital function in the first place. "I would be very curious to know what their logic was on that...and what drove them to think that was a suitable solution," said the pilot, who also spoke on the condition of anonymity.
A former Boeing pilot who tested the 737 Max, who requested anonymity due to fears of negative repercussions, told CNN "I don't think we appreciated the ramifications of a... failure of an AOA probe."
Another source familiar with the 737 MAX testing said the failure of an AOA sensor was not flight tested, but rather "analyzed in the design and certification" of the aircraft, and it was determined trained pilots would have been able to handle the failure.
A second former Boeing test pilot was surprised to learn that the company had relied on a single sensor, as opposed to a redundant system, to perform such a vital function in the first place. "I would be very curious to know what their logic was on that...and what drove them to think that was a suitable solution," said the pilot, who also spoke on the condition of anonymity.
#205
Join Date: Dec 2004
Location: Under the Cone of Silence
Programs: UA Gold; AA Dirt; HH Diamond; National Emerald; CONTROL SecretAgent Platinum; KAOS EvilFlyer Gold
Posts: 1,497
I work in IT myself and find this article very interesting:
How the Boeing 737 Max Disaster Looks to a Software Developer - IEEE Spectrum
How the Boeing 737 Max Disaster Looks to a Software Developer - IEEE Spectrum
I have not read the whole thread but this article should be of interest:
https://spectrum.ieee.org/aerospace/...ware-developer
https://spectrum.ieee.org/aerospace/...ware-developer
The piece is full of misleading comments and some downright errors. The guy's credibility is blown with such idiotic comments as implying the airplane is "dynamically unstable"; that AOA and pitch are the same thing; etc. etc. Plus implying that the DER concept is some recent innovation based upon bad intentions (it's been around since the 1940's, and I don't think FAA EVER had "armies of engineers").
True, there appear to be serious shortcomings and downright failures at Boeing in how MCAS was designed, implemented, and in the related risk assessments. But opinion pieces like this by so-called "experts" don't help the cause in investigating and fixing such failures.
Here's a link to an article that corrects many of the IEEE "article's" errors:
https://abnormaldistribution.org/ind...liner-crashes/
#206
Join Date: May 2009
Location: South Park, CO
Programs: Tegridy Elite
Posts: 5,678
Looks like the first of what will likely be several Congressional hearings is happening in a couple of weeks:
https://www.reuters.com/article/us-e...-idUSKCN1S74MO
https://www.reuters.com/article/us-e...-idUSKCN1S74MO
The U.S. House Transportation and Infrastructure Committee will hold a May 15 hearing on the grounded Boeing 737 MAX and the Federal Aviation Administrations (FAA) aircraft certification program, three people briefed on the matter said on Wednesday.
#207
Join Date: Feb 2002
Location: BNA
Programs: HH Gold. (Former) UA PP, DL PM, PC Plat
Posts: 8,138
Here's a link to an article that corrects many of the IEEE "article's" errors:
https://abnormaldistribution.org/ind...liner-crashes/
https://abnormaldistribution.org/ind...liner-crashes/
#208
FlyerTalk Evangelist
Join Date: Nov 2004
Location: Melbourne
Programs: ►QFWP/LTG►VA WP►HyattExpl.►HiltonGold►ALL Silver
Posts: 21,990
...
True, there appear to be serious shortcomings and downright failures at Boeing in how MCAS was designed, implemented, and in the related risk assessments. But opinion pieces like this by so-called "experts" don't help the cause in investigating and fixing such failures.
Here's a link to an article that corrects many of the IEEE "article's" errors:
https://abnormaldistribution.org/ind...liner-crashes/
True, there appear to be serious shortcomings and downright failures at Boeing in how MCAS was designed, implemented, and in the related risk assessments. But opinion pieces like this by so-called "experts" don't help the cause in investigating and fixing such failures.
Here's a link to an article that corrects many of the IEEE "article's" errors:
https://abnormaldistribution.org/ind...liner-crashes/
However, within the normal flight envelope there were occasionally certain situations occurring that would have the aircraft handle in variance with the behavior with other 737 models in the same situations.
If pilots were specifically trained on how to handle the MAX8 in those situation (with simulator time, lists etc.) then there would be less likely to be an issue.
But by doing that, it almost certainly would have required a new type certificate for pilots.
The manufacturer wished to avoid this since for revenue/expediency reasons.
To avoid this, they came up with software to make the plane emulate how, say, a 737NG would handle in those situations and it would function in such a manner so that aircrew would be oblivious to its operation.
And then, they basically did not tell the pilots about it.
Down the track, it appears the software has flaws that had it crash two aircraft.
Yes, the IEEE article has levels of hyperbowl, but the rebuttal posted does not change the above.
#209
Join Date: Feb 2006
Posts: 545
The key error seems to be in Boeing's definition of its real corporate values:
#210
FlyerTalk Evangelist
Join Date: Nov 2004
Location: Melbourne
Programs: ►QFWP/LTG►VA WP►HyattExpl.►HiltonGold►ALL Silver
Posts: 21,990
Much of this is already known but it does place many relevant facts together:
The many human errors that brought down the Boeing 737 Max - The Verge
The many human errors that brought down the Boeing 737 Max - The Verge
Last edited by serfty; May 3, 2019 at 4:09 pm