MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
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I‘m not sure about the insurance thing as I know too little about this market but that plane is going to be a ticking bomb - at least public relations wise - even when finally cleared to fly some time. Given how many of them were produced and will be delivered in future another one will be going down sooner or later. And whereas all commercial airliners in the last 50 years (maybe except the DC10) had the benefit of doubt that the root cause will most likely have a significant portion of pilot error included, the 737Max will not. So if it’s not CFIT in mountainous area and bad weather or a mid air collision, fingers will be pointed against the aircraft and it’s manufacturer.
And even the last backwoods journo from the Podunk Herald does now know that this plane was deprecated before its first flight, like a hotrod made from a chasis of a 60ies Volkswagen beetle, stretched and reengined with a supercharged direct injection engine, but without anti skid sytem.
So it’s gonna bite someone in future. The question is, will it be Boeing who will not provide a successor in medium term, the airline which is flying this 60ies plane in 2030 or the regulators who will be allowing this continue for indefinite time?
People will not care because they are all hoping to be in a different job position or retired when it is going to happen.
And even the last backwoods journo from the Podunk Herald does now know that this plane was deprecated before its first flight, like a hotrod made from a chasis of a 60ies Volkswagen beetle, stretched and reengined with a supercharged direct injection engine, but without anti skid sytem.
So it’s gonna bite someone in future. The question is, will it be Boeing who will not provide a successor in medium term, the airline which is flying this 60ies plane in 2030 or the regulators who will be allowing this continue for indefinite time?
People will not care because they are all hoping to be in a different job position or retired when it is going to happen.
Last edited by BDAttitude; 9th Nov 2019 at 12:40.
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Sounds like the MCAS solution might be all but there but they are now struggling with a much harder one to solve. I was wondering why the trip to Cedar Rapids when Boeing wrote the software. Looks like they are back at the FCC oem trying to show how two computers can self check each other and figure out who's wrong. Good luck with that.
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Sounds like the MCAS solution might be all but there but they are now struggling with a much harder one to solve. I was wondering why the trip to Cedar Rapids when Boeing wrote the software. Looks like they are back at the FCC oem trying to show how two computers can self check each other and figure out who's wrong. Good luck with that.
.Still I am more worried by the changes to the task system or function distribution they likely had to do due to the AP disconnect issue. There you have the potential to break anything anywhere and require to do a 100% coverage of functional testing. It’s like rebuilding the supporting walls of a house without moving the furniture. It’s never going to happen without some losses.
From : "After Lion Air crash, Boeing doubled down on faulty 737 MAX assumptions
Nov. 8, 2019 at 6:42 pm Updated Nov. 8, 2019 at 7:57 pm By Dominic Gates" :
A flawed process
The U.S. House Transportation and Infrastructure Committee, which displayed one slide from Boeing’s presentation during an appearance by CEO Muilenburg at a hearing last week, provided all 43 slides in the document at the request of the Seattle Times. The presentation is titled “MCAS Development and Certification Overview.”
It notes that MCAS was not evaluated as an individual system that was “new/novel on the MAX.” The significance of this term is that the FAA is required to be closely involved in the testing and certification of any new and novel features on an aircraft.
Though MCAS was new on the MAX version of the 737, Boeing argued that it wasn’t new and novel because a similar system “had been previously implemented on the 767” tanker for the Air Force.
Yet MCAS on the MAX was triggered by just one of the jet’s two angle-of-attack sensors, whereas MCAS on the 767 tanker compared signals from both sensors on the plane. When asked after the second crash to explain why the airliner version lacked this same redundancy, Boeing’s response was that the architecture, implementation, and pilot interface of the KC-46 tanker MCAS were so different that the two systems shared little but the acronym."
How can Boeing seriously square these contradictory statements? MCAS is similar and dissimilar at the same time?
This is 'Alice in Wonderland' time :
“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.” “The question is,” said Alice, “whether you can make words mean so many different things.”
Nov. 8, 2019 at 6:42 pm Updated Nov. 8, 2019 at 7:57 pm By Dominic Gates" :
A flawed process
The U.S. House Transportation and Infrastructure Committee, which displayed one slide from Boeing’s presentation during an appearance by CEO Muilenburg at a hearing last week, provided all 43 slides in the document at the request of the Seattle Times. The presentation is titled “MCAS Development and Certification Overview.”
It notes that MCAS was not evaluated as an individual system that was “new/novel on the MAX.” The significance of this term is that the FAA is required to be closely involved in the testing and certification of any new and novel features on an aircraft.
Though MCAS was new on the MAX version of the 737, Boeing argued that it wasn’t new and novel because a similar system “had been previously implemented on the 767” tanker for the Air Force.
Yet MCAS on the MAX was triggered by just one of the jet’s two angle-of-attack sensors, whereas MCAS on the 767 tanker compared signals from both sensors on the plane. When asked after the second crash to explain why the airliner version lacked this same redundancy, Boeing’s response was that the architecture, implementation, and pilot interface of the KC-46 tanker MCAS were so different that the two systems shared little but the acronym."
How can Boeing seriously square these contradictory statements? MCAS is similar and dissimilar at the same time?
This is 'Alice in Wonderland' time :
“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.” “The question is,” said Alice, “whether you can make words mean so many different things.”
How can Boeing seriously square these contradictory statements? MCAS is similar and dissimilar at the same time?
This is 'Alice in Wonderland' time :
“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.” “The question is,” said Alice, “whether you can make words mean so many different things.”
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Sorry but i disagree, first of all we need to classify if MCAS is a stall warning or a stall identification system, once we define that we can define what are the actions required. According to certification a pilot should be able to disable a stall id system and such system should not be prone to a single failure. That is not the case of MCAS. To off it pilots loose all electrical controls on the stab, and MCAS is prone to single AoA failure, that is the reason why it was classified as a augmentation system...when in my opinion is a stall ID system... cutting corners to solve major issue
So I am sure this has already come up many times, but can the MAX be certified without MCAS even if that required a new type rating G-d forbid? My Lake Amphibian would pitch down with power increases and vice versa. That idiosyncrasy was covered in transition lesson #1.
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However, aside from that, what they are talking about is not only really hard, but now you have to test scenarios of erronious computer shutdown at any frigging time during the duration of the flight. This is really the same rancid logic behind MCAS; a solution for an extremely rare event now creates its own problem in much more common situations. How many benign problems are in the processing code that are now going to trigger this 'kill' subroutine? What happens if the two computers get into a war with each other? How robust is the communication line between the computers, which was probably never designed to deal with the amount of data that now has to be transferred?
No wonder they did not want to completely document what they did.
No wonder they did not want to completely document what they did.
Triple modular redundancy has three systems and a majority voting system for a reason: if you can't trust a single module to be sufficiently reliable at performing its own operation, how can you possibly trust it to monitor the dual redundant module sufficiently reliably to trust it to shut it down!? And trying to add this on to a system that was never designed, in a rush to get ungrounded... sounds terrifying.
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Sorry but i disagree, first of all we need to classify if MCAS is a stall warning or a stall identification system, once we define that we can define what are the actions required. According to certification a pilot should be able to disable a stall id system and such system should not be prone to a single failure. That is not the case of MCAS. To off it pilots loose all electrical controls on the stab, and MCAS is prone to single AoA failure, that is the reason why it was classified as a augmentation system...when in my opinion is a stall ID system... cutting corners to solve major issue
The MAX needs to be re certified from scratch !
Last edited by jdawg; 9th Nov 2019 at 15:32.
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Stall identification is a misleading term. It’s task is NOT to identify a stall situation to the pilots - like a stall horn or stick shaker - but to identify an approaching stall condition with its sensors and actively reduce the AoA (like a stick pusher, alpha protect, etc.)
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It has been "common knowledge" for a long time and I've never seen or heard otherwise from an authoritative source.
FWIW, the mere reliance on the 80286 doesn't really alarm me, but the magnitude of the task of fully reconfiguring the operation of the FCCs is . . . well, it's a very big deal.
FWIW, the mere reliance on the 80286 doesn't really alarm me, but the magnitude of the task of fully reconfiguring the operation of the FCCs is . . . well, it's a very big deal.
Salute!
How come we can not talk ancient processors over on Tech Log? Keep the management and political stuff here?
Good grief! The sfwe and object code for the MCAS function could be implemented on a 8088 or a Motorola cpu from the original Apple.
We flew the SLUF and the early Vipers with such, and less than a megabyte of RAM. Our non-volatile memory was maybe a few megs, and the same boxes were used in the lunar landing module. Sheesh.
The problem is not the CPU, nor the dedicated MCAS code. The problem is integrating a new function via the autopilot sfwe boxes, STS function, and who knows what else? No excuse for a complete re-write and still using grandfather cert, huh?
Basic aero still a big problem for this old pilot, so I am with folks that want to see raw MAX flight tests that have MCAS erased and look at the plots. Unless you go "full authority" FBW, the basic aero problems with the new motors and such cannot be mitigated with crude algorithms inserted in autopilot and STS functions such as we are led to see for MCAS.
Gums sends....
How come we can not talk ancient processors over on Tech Log? Keep the management and political stuff here?
Good grief! The sfwe and object code for the MCAS function could be implemented on a 8088 or a Motorola cpu from the original Apple.
We flew the SLUF and the early Vipers with such, and less than a megabyte of RAM. Our non-volatile memory was maybe a few megs, and the same boxes were used in the lunar landing module. Sheesh.
The problem is not the CPU, nor the dedicated MCAS code. The problem is integrating a new function via the autopilot sfwe boxes, STS function, and who knows what else? No excuse for a complete re-write and still using grandfather cert, huh?
Basic aero still a big problem for this old pilot, so I am with folks that want to see raw MAX flight tests that have MCAS erased and look at the plots. Unless you go "full authority" FBW, the basic aero problems with the new motors and such cannot be mitigated with crude algorithms inserted in autopilot and STS functions such as we are led to see for MCAS.
Gums sends....
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But what is this copper foil shielding in a specific part of the wing issue ? Isn't it standard practice everywhere in the plane, and what is so special and so costly about the leading edge ?
Salute!
How come we can not talk ancient processors over on Tech Log? Keep the management and political stuff here?
Good grief! The sfwe and object code for the MCAS function could be implemented on a 8088 or a Motorola cpu from the original Apple.
We flew the SLUF and the early Vipers with such, and less than a megabyte of RAM. Our non-volatile memory was maybe a few megs, and the same boxes were used in the lunar landing module. Sheesh.
The problem is not the CPU, nor the dedicated MCAS code. The problem is integrating a new function via the autopilot sfwe boxes, STS function, and who knows what else? No excuse for a complete re-write and still using grandfather cert, huh?
Basic aero still a big problem for this old pilot, so I am with folks that want to see raw MAX flight tests that have MCAS erased and look at the plots. Unless you go "full authority" FBW, the basic aero problems with the new motors and such cannot be mitigated with crude algorithms inserted in autopilot and STS functions such as we are led to see for MCAS.
Gums sends....
How come we can not talk ancient processors over on Tech Log? Keep the management and political stuff here?
Good grief! The sfwe and object code for the MCAS function could be implemented on a 8088 or a Motorola cpu from the original Apple.
We flew the SLUF and the early Vipers with such, and less than a megabyte of RAM. Our non-volatile memory was maybe a few megs, and the same boxes were used in the lunar landing module. Sheesh.
The problem is not the CPU, nor the dedicated MCAS code. The problem is integrating a new function via the autopilot sfwe boxes, STS function, and who knows what else? No excuse for a complete re-write and still using grandfather cert, huh?
Basic aero still a big problem for this old pilot, so I am with folks that want to see raw MAX flight tests that have MCAS erased and look at the plots. Unless you go "full authority" FBW, the basic aero problems with the new motors and such cannot be mitigated with crude algorithms inserted in autopilot and STS functions such as we are led to see for MCAS.
Gums sends....
The UK navy fleet are still running on Windows XP.
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It is understandable that Boeing considers changing the rudder cables routing "unpracticable".
But what is this copper foil shielding in a specific part of the wing issue ? Isn't it standard practice everywhere in the plane, and what is so special and so costly about the leading edge ?
But what is this copper foil shielding in a specific part of the wing issue ? Isn't it standard practice everywhere in the plane, and what is so special and so costly about the leading edge ?
Edit: I found this article in B's Aero Magazine: https://www.boeing.com/commercial/ae...les/2012_q4/4/
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The real reason is obvious: the Silicon valley techie won‘t do the job for $9 an hour.