6 ms·

That's not really accurate. Boeing is under continuous attack by hatchet jobs like this that insinuate they cut corners and are solely responsible for these acc

by ackfoo 7y ago

That's not really accurate. Boeing is under continuous attack by hatchet jobs like this that insinuate they cut corners and are solely responsible for these accidents. First, we don't have final reports from the investigators yet, so it's awfully early to point the finger. Second, every major aviation accident is multi-factorial. It's never just one failure that causes it. If it does turn out to be the faulty AOA indicator causing the electric trim to go nose-down, there are still a number of other obvious contributing factors in addition to the faulty sensor. The public is demanding low airfare prices because they are getting squeezed by the increasing disparity of wealth worldwide. Wages are not rising as fast as prices, and as the cost of doing business with China slowly rises due to the trade war, prices start to creep up and the squeeze increases. Airlines respond by flying pilots with lower time and lesser training, paying them less, and working them harder. Pilots spend less time in the simulator working on abnormal conditions, and while they are undoubtedly great at monitoring normal flights and navigating controlled airspace, they have less experience hand-flying approaches and dealing with rare equipment failures and emergencies. Every pilot should have adequate simulator time to be competent with every emergency procedure for which there is a checklist, but that is not the reality. The three seconds allotted by the FAA to diagnose critical systems failures is simply not enough if you can't find and execute the correct checklist in that time period. In the old days, every single pilot from a Cessna 152 on up knew exactly what a badly trimmed airplane felt like and how to fix it instantly. When you felt that extra force on the controls, you would instinctively rotate the trim wheel in the direction of the force that you were needing to apply. Same for electric trim systems: if the force doesn't ease the way it should, you have a runaway and you need to interrupt power to the electric trim system. But that is hand-flying, stick-and-rudder-type stuff. If you're not getting the hand-flying time and the simulated failure time, you just don't develop that instinct. It's not entirely Boeing's fault that an aircrew can't recognize and counter a runaway electric trim, no matter what the details in the flight manual. It's only reasonable to assume that basic level of competency.

sgwae 7y ago
Has the same issue happened for airbus with half a thousand dead, and any of their planes grounded world wide?
- selectodude 7y ago
  The A330 had some weird pitch down incidences due to a faulty ADIRS, and obviously AF447 due to faulty pitot tubes and the completely idiotic issue where the control sticks aren't synced and the inputs are averaged out before being sent to the plane. There were some considerations given to grounding the fleet, whether or not Airbus wanted to admit it at the time. https://www.reuters.com/article/us-france-plane-denial-sb/airbus-denies-planning-to-ground-a330-340-fleet-idUSTRE5597AC20090610 https://www.reuters.com/article/us-france-plane-denial-sb/ai...
  - cjbprime 7y ago
    A330 has fewer total fatalities over its 27 years of service (339 deaths) than the MAX does in a year and a half (346 deaths).
  - raverbashing 7y ago
    The pitch down incidents I believe were caused by a non compliant part replacement (I don't remember which company it was though)
- sidlls 7y ago
  There are several pilots who've had this very issue happen to them and they managed to diagnose and address the problem without flying the plane into the ground. These incidents are almost always the result of a combination of errors ranging from negligent engineering and documentation to mechanical defects to human (pilot) error. We simply don't know all the facts in these two crashes. The publicly available information to me indicates negligent documentation (pilot manuals should have been updated to reflect the new mode and how to treat the issue similarly to runaway trim), negligent sales practice (the AoA disagree feature shouldn't be an option), and poor reactions by the pilots involved. But that's purely speculation at this point: there could very well be some other causes instead of or in addition to these.
- rootusrootus 7y ago
  Is that a serious question, or did you just not do any research? Yes, Airbus planes have crashed due to malfunctioning automation. It hasn't even been that long since one of their newest planes actually experienced a problem eerily similar to the 737MAX issue, but got lucky in that it occurred when the plane was higher and had more altitude to trade for time and the pilots were able to regain control.
asmithmd1 7y ago
All pilots of Boeing aircraft know that when the autopilot is off, there is no automation between the controls and the control surfaces - until the 737 Max changed that. The MCAS system is only active when autopilot was off, a big change. Imagine the faulty AoA sensor is causing the aircraft to hunt around to different altitudes. The pilot switches off autopilot by just applying force to the controls and suddenly the plane starts pitching down.
- lsh123 7y ago
  Not a Boeing driver, but in a few GA aircraft I flew, runaway trim can happen regardless of AP on/off status.
  - ams6110 7y ago
    Yes it can happen due to a jammed switch, relay, wiring short, etc.
- foldr 7y ago
  >All pilots of Boeing aircraft know that when the autopilot is off, there is no automation between the controls and the control surfaces This isn't even approximately true. Pretty much all passenger jets since the 50s and 60s have had yaw dampeners, for example.
  - asmithmd1 7y ago
    True, but a yaw dampener is sort of like a steady cam, it isn't going to over-rule a pilot's rudder input. Put yourself in the seat of a pilot who has flown an electro-hydraulic 737 for years. Something "funny" seems to be going on with the trim, so you take control and the trim seems to be working perfectly while you manually toggle it, but then the MCAS kicks back in after 5 seconds and tries to push the nose down again. This kind of behavior is coming from a system Boeing did not tell the pilots about.
    - zaroth 7y ago
kalleboo 7y ago
I agree with most of your points in general, but Boeing tried as hard as possible to pretend MCAS needed no training. There WAS no simulator scenario to train on for this failure.
- rootusrootus 7y ago
  Based on accurate descriptions of the intended scenario for MCAS, they would be right. When the system is working, it does what it was designed to do. The failure mode when an AOA sensor goes on the fritz is the problem. The proposed fix is what they should have shipped out with the first plane, that's the real failure here -- someone at Boeing surely saw this coming and raised a flag, and got shouted down. A reckless decision given that the 737 is a cash cow and historically such a successful line of planes that I imagine Boeing would be keen to keep the reputation intact.
  - cjbprime 7y ago
    Sort of with you, but I think once you're willing to admit that MCAS failure can be catastrophic, airworthiness regulations may require three AoA sensors (as Airbus planes have) so that you get error correction, rather than the two that should have been being used to detect disagreement (but weren't).
    - ams6110 7y ago
      I think the issue is that Boeing didn't see a potential MCAS failure as really any different from any other cause of runaway trim, for which there was well-established procedure and training. Clearly at least not all pilots seem to recognize this in time, particularly with other distractions caused by a faulty AoA reading, such as stick shaker, other warnings and alarms, and all of that happening at low altitude.
      - cjbprime 7y ago
        I don't think that matters here, though I agree with what you said. There's also going to be redundancy on the other mechanisms that can lead to runaway trim, because runaway trim can be catastrophic, because we don't assume that pilots are perfect, and because (as you say) runaway trim can happen in situations where the ground will necessarily arrive before your recovery does. I think it takes around thirty seconds for the trim motor to move you from one end (where both crashed planes had it) of the jackscrew to the other. And that's with the motor! If you cut out the motor because it was literally trying to kill you -- and as Boeing advises you to -- you'll have to use the hand crank and it will take much longer. Runaway trim at low altitude is death. It really seems to me that the MAX as shipped was not plausibly airworthy (due to the use of a single sensor). I think even Boeing's going to agree eventually.
cjbprime 7y ago
> If it does turn out to be the faulty AOA indicator causing the electric trim to go nose-down, there are still a number of other obvious contributing factors in addition to the faulty sensor. There's no serious argument here. It isn't airworthy on an airliner to have a system with flight control capability using one sensor with no redundancy. It doesn't happen anywhere else and there are regulations that forbid it. Airbus uses AoA for autopilot and therefore puts three AoA sensors on the plane with majority voting. It appears that Boeing (during certification) either lied about the severity of MCAS failure, or lied and said they were using two sensors when they weren't.
deleted 7y ago
[deleted]
salawat 7y ago
Boeing is solidly at fault here. I have to preach the idea that networks and computing are not magic. While yes, I cam talk to people all over the world, the information I'm trying to communicate still has to be put in front of a person to be communicated. An aircraft company should treat information dissemination to pilots as as critical a toolchain as their supply and manufacturing processes. If your tool cannot be used safely, your job isn't done, no matter what your marketing people say. If it were a financial services, or big data cpmpany maybe I'd lend credence to the safety of leaving that out. Not aviation. There is too much at risk there. Flight is the equivalent of riding a bubble of air to your destination, which necessitates the continuous balancing of aerodynamic forces, facilitated by increasingly complex hybrid systems of direct human control and automation. At the end of the day though, a pilot/plane combination should be able to be salvaged even with catastrophic loss of piloting aids, even with catastrophic loss of integrity of the automation on board. Automation should make flying a plane easier. Not render pilots ineffective when it malfunctions or fails.

by ackfoo 7y ago

sgwae 7y ago

Has the same issue happened for airbus with half a thousand dead, and any of their planes grounded world wide?

selectodude 7y ago
The A330 had some weird pitch down incidences due to a faulty ADIRS, and obviously AF447 due to faulty pitot tubes and the completely idiotic issue where the control sticks aren't synced and the inputs are averaged out before being sent to the plane. There were some considerations given to grounding the fleet, whether or not Airbus wanted to admit it at the time. https://www.reuters.com/article/us-france-plane-denial-sb/airbus-denies-planning-to-ground-a330-340-fleet-idUSTRE5597AC20090610 https://www.reuters.com/article/us-france-plane-denial-sb/ai...
- cjbprime 7y ago
  A330 has fewer total fatalities over its 27 years of service (339 deaths) than the MAX does in a year and a half (346 deaths).
- raverbashing 7y ago
  The pitch down incidents I believe were caused by a non compliant part replacement (I don't remember which company it was though)
sidlls 7y ago
There are several pilots who've had this very issue happen to them and they managed to diagnose and address the problem without flying the plane into the ground. These incidents are almost always the result of a combination of errors ranging from negligent engineering and documentation to mechanical defects to human (pilot) error. We simply don't know all the facts in these two crashes. The publicly available information to me indicates negligent documentation (pilot manuals should have been updated to reflect the new mode and how to treat the issue similarly to runaway trim), negligent sales practice (the AoA disagree feature shouldn't be an option), and poor reactions by the pilots involved. But that's purely speculation at this point: there could very well be some other causes instead of or in addition to these.
rootusrootus 7y ago
Is that a serious question, or did you just not do any research? Yes, Airbus planes have crashed due to malfunctioning automation. It hasn't even been that long since one of their newest planes actually experienced a problem eerily similar to the 737MAX issue, but got lucky in that it occurred when the plane was higher and had more altitude to trade for time and the pilots were able to regain control.

asmithmd1 7y ago

All pilots of Boeing aircraft know that when the autopilot is off, there is no automation between the controls and the control surfaces - until the 737 Max changed that. The MCAS system is only active when autopilot was off, a big change. Imagine the faulty AoA sensor is causing the aircraft to hunt around to different altitudes. The pilot switches off autopilot by just applying force to the controls and suddenly the plane starts pitching down.

lsh123 7y ago
Not a Boeing driver, but in a few GA aircraft I flew, runaway trim can happen regardless of AP on/off status.
- ams6110 7y ago
  Yes it can happen due to a jammed switch, relay, wiring short, etc.
foldr 7y ago
>All pilots of Boeing aircraft know that when the autopilot is off, there is no automation between the controls and the control surfaces This isn't even approximately true. Pretty much all passenger jets since the 50s and 60s have had yaw dampeners, for example.
- asmithmd1 7y ago
  True, but a yaw dampener is sort of like a steady cam, it isn't going to over-rule a pilot's rudder input. Put yourself in the seat of a pilot who has flown an electro-hydraulic 737 for years. Something "funny" seems to be going on with the trim, so you take control and the trim seems to be working perfectly while you manually toggle it, but then the MCAS kicks back in after 5 seconds and tries to push the nose down again. This kind of behavior is coming from a system Boeing did not tell the pilots about.
  - zaroth 7y ago

kalleboo 7y ago

I agree with most of your points in general, but Boeing tried as hard as possible to pretend MCAS needed no training. There WAS no simulator scenario to train on for this failure.

rootusrootus 7y ago
Based on accurate descriptions of the intended scenario for MCAS, they would be right. When the system is working, it does what it was designed to do. The failure mode when an AOA sensor goes on the fritz is the problem. The proposed fix is what they should have shipped out with the first plane, that's the real failure here -- someone at Boeing surely saw this coming and raised a flag, and got shouted down. A reckless decision given that the 737 is a cash cow and historically such a successful line of planes that I imagine Boeing would be keen to keep the reputation intact.
- cjbprime 7y ago
  Sort of with you, but I think once you're willing to admit that MCAS failure can be catastrophic, airworthiness regulations may require three AoA sensors (as Airbus planes have) so that you get error correction, rather than the two that should have been being used to detect disagreement (but weren't).
  - ams6110 7y ago
    I think the issue is that Boeing didn't see a potential MCAS failure as really any different from any other cause of runaway trim, for which there was well-established procedure and training. Clearly at least not all pilots seem to recognize this in time, particularly with other distractions caused by a faulty AoA reading, such as stick shaker, other warnings and alarms, and all of that happening at low altitude.
    - cjbprime 7y ago
      I don't think that matters here, though I agree with what you said. There's also going to be redundancy on the other mechanisms that can lead to runaway trim, because runaway trim can be catastrophic, because we don't assume that pilots are perfect, and because (as you say) runaway trim can happen in situations where the ground will necessarily arrive before your recovery does. I think it takes around thirty seconds for the trim motor to move you from one end (where both crashed planes had it) of the jackscrew to the other. And that's with the motor! If you cut out the motor because it was literally trying to kill you -- and as Boeing advises you to -- you'll have to use the hand crank and it will take much longer. Runaway trim at low altitude is death. It really seems to me that the MAX as shipped was not plausibly airworthy (due to the use of a single sensor). I think even Boeing's going to agree eventually.

cjbprime 7y ago

> If it does turn out to be the faulty AOA indicator causing the electric trim to go nose-down, there are still a number of other obvious contributing factors in addition to the faulty sensor. There's no serious argument here. It isn't airworthy on an airliner to have a system with flight control capability using one sensor with no redundancy. It doesn't happen anywhere else and there are regulations that forbid it. Airbus uses AoA for autopilot and therefore puts three AoA sensors on the plane with majority voting. It appears that Boeing (during certification) either lied about the severity of MCAS failure, or lied and said they were using two sensors when they weren't.

deleted 7y ago

[deleted]

salawat 7y ago

Boeing is solidly at fault here. I have to preach the idea that networks and computing are not magic. While yes, I cam talk to people all over the world, the information I'm trying to communicate still has to be put in front of a person to be communicated. An aircraft company should treat information dissemination to pilots as as critical a toolchain as their supply and manufacturing processes. If your tool cannot be used safely, your job isn't done, no matter what your marketing people say. If it were a financial services, or big data cpmpany maybe I'd lend credence to the safety of leaving that out. Not aviation. There is too much at risk there. Flight is the equivalent of riding a bubble of air to your destination, which necessitates the continuous balancing of aerodynamic forces, facilitated by increasingly complex hybrid systems of direct human control and automation. At the end of the day though, a pilot/plane combination should be able to be salvaged even with catastrophic loss of piloting aids, even with catastrophic loss of integrity of the automation on board. Automation should make flying a plane easier. Not render pilots ineffective when it malfunctions or fails.