MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
I find it incredible people are still playing the pilot error card. If that was the problem, would the aircraft still be grounded 6 months on, with no realistic prospect of flying (at least outside the US) this year?
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out there > .................................................. > TRUTH
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I note that the Langewiesche storytelling is having its rather predictable effect, serving to resurrect the pilot-error arguments and to provide them with ostensible "authority." Was that the intent of the piece? It's difficult not to come to that conclusion.
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Mindful of the admonition that fools rush in where angels fear to tread, first let me repost a comment I made in a related thread....
I will add the observation that even if everyone on the planet concurs that the Boeing's design lapses (and subsequent "approval" by the FAA) was, without question, the primary cause of these accidents, there is still valid reasons to examine the factors related to aircrew training, aircraft maintenance, and corporate culture that have come to light. If one were to play a thought experiment and read Langewieshe article through the lens of an "alternate universe" in which there was a different aircraft malfunction involved and perhaps a less lethal outcome, I believe he provides a fair amount of anecdotal evidence there are serious issues with how some airlines put cost cutting ahead of safety. I think it would be a great disservice to ignore these warning signs because one or more of these lapses could very well become the primary causes of some future accident.
If nothing is done now when there is clear evidence of a problem, what are we to say later to the families of the next victims?
I am cautious about wading into the commentary about the Langewiesche NYT article, but I'm going to suggest that there is a middle ground here.
There is an old saw that goes something like, "What you see depends heavily on where you stand." Different people can look at the information surrounding the MAX crashes through different lenses and come away with different viewpoints. That's not necessarily a bad thing. Accident investigations provide the opportunity to identify multiple ways in which the aviation system can be improved, even if there is disagreement regarding the primary causes.
I read the article through several times and I'll admit that I don't agree with everything Langewieshe says, but I don't disagree with all of it either. Clearly, Boeing fell far short of everyone's expectations in how they rushed through the MAX design and production process. Just as clearly, these accidents demonstrated that there is significant room for improvement in regulatory oversight, aircrew training, aircraft maintenance, and overall corporate (both airline and manufacturer) attitudes toward safety. All of these areas need work, so there is no need to pick and choose. Boeing absolutely needs to step up and fix their design process. The FAA and other certificate authorities absolutely need to step up and improve their oversight. By the same token, airlines also need to re-evaluate their aircrew training and aircraft maintenance practices with an particular eye toward improving safety as opposed to minimizing costs. It all needs work, so I really don't think it is necessary to emphasize one problem area at the expense of another.
There is an old saw that goes something like, "What you see depends heavily on where you stand." Different people can look at the information surrounding the MAX crashes through different lenses and come away with different viewpoints. That's not necessarily a bad thing. Accident investigations provide the opportunity to identify multiple ways in which the aviation system can be improved, even if there is disagreement regarding the primary causes.
I read the article through several times and I'll admit that I don't agree with everything Langewieshe says, but I don't disagree with all of it either. Clearly, Boeing fell far short of everyone's expectations in how they rushed through the MAX design and production process. Just as clearly, these accidents demonstrated that there is significant room for improvement in regulatory oversight, aircrew training, aircraft maintenance, and overall corporate (both airline and manufacturer) attitudes toward safety. All of these areas need work, so there is no need to pick and choose. Boeing absolutely needs to step up and fix their design process. The FAA and other certificate authorities absolutely need to step up and improve their oversight. By the same token, airlines also need to re-evaluate their aircrew training and aircraft maintenance practices with an particular eye toward improving safety as opposed to minimizing costs. It all needs work, so I really don't think it is necessary to emphasize one problem area at the expense of another.
If nothing is done now when there is clear evidence of a problem, what are we to say later to the families of the next victims?
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Boeing unwittingly performed a very large scale statistical study. Given Boeing's aim was to change as little as possible in the MAX, virtually everything was constant with the exception of the MCAS software (engines and other changes have not been implicated in the accidents). Exactly as you state, same crew, same training, even the same problems & vulnerabilities with the AoA sensor (same part number, willing to be corrected). That single change has been the software.
MCAS overrides the aft-column cutout switch (not the console cutout, the one which cuts off automatic trim movement if the column is pulled far enough back) that is a hardware change. In addition to that (and possibly related - haven't seen any convincing explanation of why) the console stab trim cutout switches had a wholesale rewiring and renaming, changes that I don't think we yet understand the rationale behind or the impact of (one hopes Boeing does, but I would no longer assume that...).
The aft-column cutout would have prevented the crashes, period. Overriding it should have been a red flag. I don't know, but I can pretty much guarantee that it wasn't put there decades ago because a design team had a few spare switches and relays to use up on a Friday afternoon after a hard liquid lunch in the pub. The fact that it was necessary to override it to make MCAS work at all, doesn't justify doing it - it should in fact have been a flag that MCAS was wrong in principle. To my mind, if, to get your change to pass (safety) certification, you have to override a decades-old flight-proven safety system (that is part of the overall grandfather certification you a relying on), you are doing it wrong. You don't make things safe by overriding (existing, proven) safety systems.
Now, I'm well aware that that is "gut feel" engineering and that it isn't done that way and that there is a whole system of procedures, analyses, calculations, checks and balances that ensure that you changes to a legacy system don't screw it up... well, they didn't
work. Sometimes when procedures, calculations, computers, all say something is right, your gut still says it's wrong, and sometimes the gut is right, listen to it and override it at your peril.Overriding that switch was the point where, I think, Boeing threw their (pilot is ultimately in charge) flight controls philosophy out the window and sent the planes into the ground/sea. They headed down the Airbus HAL-knows-best route, without the backing of a properly redundant sensor system (which still ****s buses sometimes) to tell HAL what is actually going on, and now they get to repent at leisure.
[end rant, back to lurk mode...]
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The aft-column cutout would have prevented the crashes, period. Overriding it should have been a red flag. I don't know, but I can pretty much guarantee that it wasn't put there decades ago because a design team had a few spare switches and relays to use up on a Friday afternoon after a hard liquid lunch in the pub. The fact that it was necessary to override it to make MCAS work at all, doesn't justify doing it - it should in fact have been a flag that MCAS was wrong in principle.
And to you as well, gums. Good point. Salute.
Seconded, thirded and fourthed the pile-on to yanrair's comment. It seems a bit prejudiced considering that it merely dittoes Langewiesche without addressing the many detailed critiques in earlier posts here, or Lemme's surgical strike.
Tomaski has a point. If there is a widening crack in safety standards linked to the growth of low-cost carriers, particularly in nations with problems of corruption in executive government, that's a problem. But it's an independent problem from MCAS, which is specific to the MAX. It may be related to the fact that FBW+automation aircraft are two generations on from the 737, the sole in-production survivor of the manual-reversion era. But MCAS is clearly something else,
Moreover, it's not the first time in aviation history that crew training has been an issue. When we first invented CVRs, we discovered that those ace Western hairy-armed airmen were far from perfect in the way that they managed the crew, and that we had to focus on training crews as crews rather than relying on someone's time in F-106s. Personally I think that a few bullets were dodged in an era when regionals were paying peanuts for right-seaters who had eked out the requisite hours puttering around the circuit in flight-school C150s, domiciling them in Pigs Snout AR and extracting every legal hour from them.
Tomaski has a point. If there is a widening crack in safety standards linked to the growth of low-cost carriers, particularly in nations with problems of corruption in executive government, that's a problem. But it's an independent problem from MCAS, which is specific to the MAX. It may be related to the fact that FBW+automation aircraft are two generations on from the 737, the sole in-production survivor of the manual-reversion era. But MCAS is clearly something else,
Moreover, it's not the first time in aviation history that crew training has been an issue. When we first invented CVRs, we discovered that those ace Western hairy-armed airmen were far from perfect in the way that they managed the crew, and that we had to focus on training crews as crews rather than relying on someone's time in F-106s. Personally I think that a few bullets were dodged in an era when regionals were paying peanuts for right-seaters who had eked out the requisite hours puttering around the circuit in flight-school C150s, domiciling them in Pigs Snout AR and extracting every legal hour from them.
Takwis, #2469, IFF789, #2467,
It is difficult to understand how MCAS is wrong in principle. As a fix for a stability problem identified during flight test, the design (theory) was adequate (expedient, quick, low cost) although an ‘inelegant patch’ compared with changing the underlying aerodynamics - aircraft structure.
The weakness of MCAS was in its implementation - engineering, and thence safety assessment and certification.
An outstanding puzzle is why MCAS is based on AoA opposed to speed in order to cure what appears to be deficient trim-speed stability. From this arises the (false) association with stall issues, yet the existing stall alerting and protection systems remain unchanged.
Why use AoA opposed to speed?
Modifying MCAS to provide engineering and certification integrity, even if the first proposal was inadequate, should not be an onerous task within the current timescale; thus the additional issue of high trim-wheel forces could be a considerable challenge resulting in further delay.
It is difficult to understand how MCAS is wrong in principle. As a fix for a stability problem identified during flight test, the design (theory) was adequate (expedient, quick, low cost) although an ‘inelegant patch’ compared with changing the underlying aerodynamics - aircraft structure.
The weakness of MCAS was in its implementation - engineering, and thence safety assessment and certification.
An outstanding puzzle is why MCAS is based on AoA opposed to speed in order to cure what appears to be deficient trim-speed stability. From this arises the (false) association with stall issues, yet the existing stall alerting and protection systems remain unchanged.
Why use AoA opposed to speed?
Modifying MCAS to provide engineering and certification integrity, even if the first proposal was inadequate, should not be an onerous task within the current timescale; thus the additional issue of high trim-wheel forces could be a considerable challenge resulting in further delay.
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Expedient, quick, and low cost; yes, it met those goals. Until the grounding...and the lawsuits to follow. Penny wise. Correcting an aerodynamic problem with a software patch, great idea. Tickling the dragon, as Gums says. Making changes to the flight control system, without telling the pilots? Ethically, morally, and even fiduciarily; dead wrong. Using the horizontal stab as a stall prevention system? Excessive. Using one AOA vane to make critical decisions? Shortsighted. Trying to implement a semi-FBW into a manual-reversion airplane? On the cheap? Asinine. Moving the stab (repeatedly) a set amount without any check of it's initial position? Moronic. Sending this airplane out without any warning of this new system? Downright murderous.
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No time to read the whole thread , indeed several threads, and I stopped flying the 73 last year, but. . . . it is good to pop in from time to time at a moment that worthwhile comments are being posted, with thanks to , infrequentflyer789, Takwis, and gums.
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Takwis, #2469, IFF789, #2467,
It is difficult to understand how MCAS is wrong in principle. As a fix for a stability problem identified during flight test, the design (theory) was adequate (expedient, quick, low cost) although an ‘inelegant patch’ compared with changing the underlying aerodynamics - aircraft structure.
The weakness of MCAS was in its implementation - engineering, and thence safety assessment and certification.
An outstanding puzzle is why MCAS is based on AoA opposed to speed in order to cure what appears to be deficient trim-speed stability. From this arises the (false) association with stall issues, yet the existing stall alerting and protection systems remain unchanged.
Why use AoA opposed to speed?
Modifying MCAS to provide engineering and certification integrity, even if the first proposal was inadequate, should not be an onerous task within the current timescale; thus the additional issue of high trim-wheel forces could be a considerable challenge resulting in further delay.
It is difficult to understand how MCAS is wrong in principle. As a fix for a stability problem identified during flight test, the design (theory) was adequate (expedient, quick, low cost) although an ‘inelegant patch’ compared with changing the underlying aerodynamics - aircraft structure.
The weakness of MCAS was in its implementation - engineering, and thence safety assessment and certification.
An outstanding puzzle is why MCAS is based on AoA opposed to speed in order to cure what appears to be deficient trim-speed stability. From this arises the (false) association with stall issues, yet the existing stall alerting and protection systems remain unchanged.
Why use AoA opposed to speed?
Modifying MCAS to provide engineering and certification integrity, even if the first proposal was inadequate, should not be an onerous task within the current timescale; thus the additional issue of high trim-wheel forces could be a considerable challenge resulting in further delay.
It was later co-opted for the low speed regime once they started flight testing. The speed is irrelevant, it is the AOA that matters.
Also the STS does have a AND trim function related to speed. But it is separate from mcas.
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It was later co-opted for the low speed regime once they started flight testing. The speed is irrelevant, it is the AOA that matters.
Or can anyone find- report who ' survived ' on a 'max' simulator which dupicates trim forces on trim wheel at any speed, and the number of turns needed after say ONE degree of Nose down and 200 or so kts and altitude of less than 5000 AGL and done by ONE pilot- even knowing what to expect by" jamming " the AOA in a significant nose up AOA ?
Place your bets .
Has the MAX already set a record for duration of grounding or is it still only a contender? It does seem a very protracted process, with very little indication of when it might end or on what terms.
As a Boeing investor, I'd be concerned about the corrosive effect of an ongoing and apparently interminable investigation. It may be that Boeing will have to cut bait, because this process leaves them paralyzed, just waiting for the regulators.
As a Boeing investor, I'd be concerned about the corrosive effect of an ongoing and apparently interminable investigation. It may be that Boeing will have to cut bait, because this process leaves them paralyzed, just waiting for the regulators.
Psychophysiological entity
How many millions of 737 departures have there been since 1967? As far as I can determine, not a single of the 172 hull loss on the 737 has been attributed to a runaway trim prior to the MAX. Two in a very short space of time for the MAX? That is why airworthiness authorities had to act.
Infrequent said :
The aft-column cutout would have prevented the crashes, period. Overriding it should have been a red flag.
Given that STS is tried and tested, it doesn't seem unreasonable at face value to use such a system for offsetting the unwanted reduction in stick load. It seems that it was the way the algorithms were so radically altered that caused the frightening speed of AND adjustment. However, I'm not sure if the original rate would have complied. But added to this there was what is effectively a re-datumisation of the stabilizer angle which allowed summing of the AND bursts.
Takwis said:
. . . Moving the stab (repeatedly) a set amount without any check of it's initial position? Moronic. . . .
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Airplane groundings are rare. Here are some of history's biggest
A History Of Aircraft Groundings (The Early Years – Part 1)
The Live and Let's Fly story is the first of three parts. If you go back to the home page, you can get to the next two.
The Comet was grounded in April 1954 and resumed commercial service in late 1958 after extensive modifications and testing, so Boeing still have a long way to go. It's worth noting that during the grounding the British aircraft industry lost the lead to the Americans and never recovered.
