191–200 of 317 posts
NTSB apparently need better employees for making such a recommendation... (ie: it is not ok for 1/2 of the pilots to not be 100% in control of their plane)
100% control of any complex system does not and can not exist.
To me, the thrust of the article is on making sure human factors are incorporated into flight certification process. As they highlight, although uncommanded MCAS input was part of the certification tests, it was only marked as a 'major' risk rather than more severe classifiers. This wasn't because of any phenomenal test pilots, but just because the FAA (rather than Boeing) guidelines behind the certification assume immediate assessment and diagnosis of the issue.
The report goes into a lot of depth about other human factors, for example, how transport-category planes should have straightforward highlighting of the primary issue since often the primary cause bubbles through various interconnected systems, and the main pilot response tends to be to identify the root cause under stress and then having to fix it.
To the extent I could re-summarize the report, I'd say "Plane Certification Processes Must Consider Real-World Scenarios And Factor Human Response to In-Flight Failures in Plane Design"
Earlier quoted context omitted.
>Though I can’t help but wonder if this is a very subtle re-framing of the Max accidents to shift blame back towards pilots. Blame is a loaded word. Boeing assumed that pilots could be relied upon to recover from a MCAS induced runaway trim. Practice has shown that they can't. Whether Boeing or the pilots is at fault is, from a safety perspective, irrelevant. The bottom line is that an assumption was made, it was wro…
I appreciate the attempt to be diplomatic, and I agree that using average pilots is sensible. But, with respect, I could not disagree more with the rest of that. > Blame is a loaded word. Boeing’s response to the accidents was to blame the pilots, there is precedent for this word in this situation. https://www.cnn.com/2019/05/23/business/american-airlines-bo... > Boeing assumed that pilots could be relied upon No, Bo…
There are many, many things that went wrong:
1. The stuck AOA instrumentation on the plane.
2. MCAS not using redundant AOA information and being fooled by the stuck instrumentation.
3. Lack of clear indication of what MCAS was doing contributing to flight crew confusion.
4. Improper execution of the runaway trim procedure/checklist by flight crew.
5. Training shortcomings about MCAS in particular.
6. Operator / national regulator training shortcomings in dealing with runaway trim procedure.
If you remove any of these links in the chain, the crash is less likely to happen. Good risk management tries to improve all of them.
#5 that you mention is important. #4 / #6 are important, too -- jurisdictions that emphasized this training produced flight crews that did the right things and survived. #2 and #3 are most important, IMO, and even #1 deserves some thought (can the instrumentation be made better/more reliable?)
I say #2/#3 are most important because using training alone to fix a system that does tricky things at a difficult time is a band-aid, and is going to let some of the accident scenarios through.
Earlier quoted context omitted.
This assumes the skill variance among pilots is pretty low. Average not in skill (I don’t think there’s a way to rate or rank pilots) but in specialised Boeing plane specific training. The problem with Boeing’s assumption was that pilots would have specialised training on that model, and the regulators seem to be trying to remediate that.
If the skill variance is pretty low then you might as well use test pilots. Their skill will hardly be better then the worst of the worst. I don't think there is actual data on skill variance among professional airline pilots so I rather they just force testing on groups which are statistically more significant to get into crashes.
The point of the test flight is to push the plane as far as it will go. Practically all drivers, regardless of skill level, will lose control if you have them hydroplane a car. Race drivers will not. With a couple advanced driving classes suddenly most people will be able to handle a slide much better. There's a gap in experience, not talent. There is no such gap between any two normal drivers.
Earlier quoted context omitted.
>Though I can’t help but wonder if this is a very subtle re-framing of the Max accidents to shift blame back towards pilots. Blame is a loaded word. Boeing assumed that pilots could be relied upon to recover from a MCAS induced runaway trim. Practice has shown that they can't. Whether Boeing or the pilots is at fault is, from a safety perspective, irrelevant. The bottom line is that an assumption was made, it was wro…
>Boeing assumed that pilots could be relied upon to recover from a MCAS induced runaway trim. The incidents of MCAS errors with US pilots who reported it to the FAA did result in recovery. But later cases did result in tragic accidents. https://static.seattletimes.com/wp-content/uploads/2018/11/L... But when you make that statement, I don't think you're really imagining what it would be like to be on a plane like tha…
This was specifically removed from the MAX to accommodate MCAS.
Earlier quoted context omitted.
I appreciate the attempt to be diplomatic, and I agree that using average pilots is sensible. But, with respect, I could not disagree more with the rest of that. > Blame is a loaded word. Boeing’s response to the accidents was to blame the pilots, there is precedent for this word in this situation. https://www.cnn.com/2019/05/23/business/american-airlines-bo... > Boeing assumed that pilots could be relied upon No, Bo…
In aviation we tend to look at failure chains . There are many, many things that went wrong: 1. The stuck AOA instrumentation on the plane. 2. MCAS not using redundant AOA information and being fooled by the stuck instrumentation. 3. Lack of clear indication of what MCAS was doing contributing to flight crew confusion. 4. Improper execution of the runaway trim procedure/checklist by flight crew. 5. Training shortcomi…
Specifically it's the argument in the article that large disasters often have multiple causes. "Perrow says, Murphy's Law is wrong—what can go wrong usually goes right. But then one day a few of the bad little choices come together, and circumstances take an airplane down. Who, then, is really to blame?"
In large disasters, sometimes several not very likely simultaneous failures happen at the same time.
"The ValuJet accident is different. I would argue that it represents the third and most elusive kind of disaster, a "system accident," which may lie beyond the reach of conventional solution, and which a small group of thinkers, inspired by the Yale sociologist Charles Perrow, has been exploring elsewhere—for example, in power generation, chemical manufacturing, nuclear-weapons control, and space flight. Perrow has coined the more loaded term "normal accident" for such disasters, because he believes that they are normal for our time. His point is that these accidents are science's illegitimate children, bastards born of the confusion that lies within the complex organizations with which we manage our dangerous technologies. Perrow is not an expert on commercial flying, but his thinking applies to it nonetheless. In this case the organization includes not only ValuJet, the archetype of new-style airlines, but also the contractors that serve it and the government entities that, despite economic deregulation, are expected to oversee it."
I'd have to assume the pilots in some fashion would be incentivised to not be chosen to test for fear of simply being an average pilot in the first place.
Uh oh. What are they going to do when they discover that there aren't any average pilots? https://www.thestar.com/news/insight/2016/01/16/when-us-air-... (HN discussion: https://news.ycombinator.com/item?id=11230287 ) https://www.theatlantic.com/business/archive/2016/02/the-inv... (HN discussion: https://news.ycombinator.com/item?id=11155889 )
I love those articles, and the lesson learned from them. But there is no automatic parallel in this situation, in fact the opposite here. The NTSB isn’t suggesting that Boeing model a single “average” pilot. They’re suggesting that Boeing test using many pilots who are not highly trained in test procedures. The “flaw of averages” problem is one of combining averages in multiple dimensions and assuming the result is s…
- Either it’s Boeing’s fault for improper UX,
- Either it’s Boeing’s fault for pilot certifications not being stringent enough.
In either case, the aircraft manufacturer must improve. I think of it as an “integration test”, “let’s see how the pilot+plane integrate together”.
Not necessarily Boeing, btw. It could be Airbus. It could even be a move from the US regulator which advantages Boeing compared to Airbus depending on whether Airbus planes were tested with skilled pilots.
Earlier quoted context omitted.
Also this test pilots may know the inner working of the plane where the real pilots were not told that MCAS was added behind their backs and some buttons/switches changed behavior. Also were this test pilots had accessed to extra diagnose data where regular pilots were not provided even with a sensor disagree message
There wouldn't be a sensor disagree message because there was only one AOA sensor, prone to failure, with no redundancy.