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Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

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Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#241

Post by IllogicalLogic »

avar wrote: post #209
kayfox wrote: post #132

Earlier quoted context omitted.

The general idea was that pilots would correctly recognize large amounts of undesired and uncommanded trim being runaway trim and perform the checklist to resolve that issue that they are expected to know by memory, since there is a need to execute it fast, without paging through the Quick Reference Handbook. This is not a checklist that was introduced with the 737 MAX, but one that has existed since the introduction…

> "Boeing's designs reflect a US-centric expectation of pilots" So we are expected to believe that Boeing never connected the dots between: 1. We design planes for US pilots 2. We sell planes abroad 3. Incidents abroad can ground an entire aircraft series This makes them seem more incompetent, not less. It's not like they have no say in what's considered standardized training for the series.

It's an appeal to "intelligence of operator" to coverup for poor design.

Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#242

Post by mlyle »

jakeogh wrote: post #236
mlyle wrote: post #231

Earlier quoted context omitted.

Better avoid Airbus, then, because there's a massive control law between the pilots and the actuators to create a "do what I mean" interface with envelope protection and all kinds of characteristics tamed. https://www.skybrary.aero/index.php/Flight_Control_Laws#Norm... Boeing has mostly avoided that. MCAS is kind of an unusual form of control augmentation as far as Boeing is concerned.

Thanks. I couldnt agree more. It would make sense if the bar was higher for adding control software than training pilots. To me it seems like the type cert problem was backwards.

In fairness, we've added a whole lot of automation since 1970, and most people think that increased automation has been a key factor in why aviation is so much safer overall. (Along with crew resource management).

Automation definitely has directly killed people, though, too.

Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#243

Post by dmitrygr »

dahart wrote: post #196
mlyle wrote: post #193

Earlier quoted context omitted.

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…

Agreed! Your comment reminds me a lot of this 1998 article about the ValuJet crash in Flordia https://www.theatlantic.com/magazine/archive/1998/03/the-les... 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 air…

This is called the "Swiss cheese model of accident causation" and it is commonly used to discuss airplane accidents. https://en.wikipedia.org/wiki/Swiss_cheese_model

Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#245

Post by sdfafafa »

If we assume the distribution of pilot talent for a Max 737 is symmetrical, then mean=median so the tests only require the better half of pilots land the plane.

Which is a pretty bad standard.

A better standard is that the 20% percentile commerical pilot can land the plane.

Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#246

Post by sdfafafa »

EdgarVerona wrote: post #165
rowanG077 wrote: post #81

Actually they must use the worst pilots. If they use average pilots that means 50% of the pilots might be out of their depth flying that plane. What kind of insanity is this?

I agree. Though I would also feel pretty disheartened if I got a call from them after that decision was made - "Hey, we need someone of your skill level to come in and fly some test planes" "...okay"

Naw, you have everyone try to recover the plane in the simulator.

The Max needs to ensure that 80% ("average" is too low a standard) of tested pilots recover the plane.

The other 20% take remedial classes.

Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#247

Post by MaupitiBlue »

heisenbit wrote: post #219
mlyle wrote: post #193

Earlier quoted context omitted.

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…

Nope, the excessive authority given to MCAS in combination with the hard to rewind trim (particularly at high speeds) were a mousetrap to be sprung. There are many ways to trigger this mousetrap. This is not a chain, this is a cluster with many chains hanging from it.

Correct. Many factors contributed, but there was one prevailing factor - the defective design of MCAS.

Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#248

Post by inimino »

anigbrowl wrote: post #233
inimino wrote: post #162

Earlier quoted context omitted.

"Simplify and streamline" is exactly not the solution here, in fact the issue was that the relevant information was invisible and hidden from pilots, not that there was too much. Not everything in good design needs to end up looking like a Fischer-Price toy. The main problems from my limited understanding were: pilots didn't know the subsystem existed; they didn't know it had activated; they didn't know what it was d…

True, but too much instrumentation is also a problem. I'm into synthesizers, which run the gamut from bleep-bloop toys to movie-soundtrack in a box. Mostly, synths are marketed like 'Not only can the Omnicron Neutron Wrangler produce any sound imaginable, it can produce more of them more loudly than the competition and audiences will surely be impressed by your mastery of its mind-bogglingly vast control surface.' Bu…

That's true, but the design constraints are very different. If your synth had a system in it that could fail, and another system responsible for monitoring that first system, and potentially overriding it, and if that system failure required you to take immediate and very specific action to prevent your synth from turning into a fireball, you'd want probably want a more or less one-to-one mapping between those subsystems and the instrumentation that you're looking at.

The well-loved classics you describe sound more like making a plane that's aerodynamically hard to lose control of... which is kind of a holy grail, but the MCAS design came after all of that was fixed by earlier design decisions.

Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#249

Post by mark-r »

anigbrowl wrote: post #223
mark-r wrote: post #149

Earlier quoted context omitted.

A friend of mine was once told to make his product idiot-proof. He said "sure, as soon as you give me the spec for the standard idiot."

That's a really old joke and its purpose is to deflect rather than to illuminate. Your friend was trying to sound smart to distract from his unwillingness or inability to come to grips with the underlying design issues.

Maybe it was an old joke, but it was new to me at the time - only time I had heard it, and I haven't heard it again in the many years since.

And I think it says something useful about the impossibility of the task. The domains we work in are all about the expected inputs and expected outputs, and it takes a special kind of imagination to come up with parameters outside of those.

Re: Plane Tests Must Use Average Pilots, NTSB Says After 737 Max Crashes

#250

Post by serf »

anigbrowl wrote: post #223
mark-r wrote: post #149

Earlier quoted context omitted.

A friend of mine was once told to make his product idiot-proof. He said "sure, as soon as you give me the spec for the standard idiot."

That's a really old joke and its purpose is to deflect rather than to illuminate. Your friend was trying to sound smart to distract from his unwillingness or inability to come to grips with the underlying design issues.

>Your friend was trying to sound smart to distract from his unwillingness or inability to come to grips with the underlying design issues.

Stout claim.

So I presume that you've witnessed any design or engineering firm that was able to deal with every 'idiot' within their problem domain?

I think OPs interpretation of the saying is more correct. The saying is bringing up the impossibility of designing something for everyone , not the deflecting of labor in some snarky way.

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