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Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

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Re: Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

#261

Post by veryworried »

jyounker wrote: post #221
veryworried wrote: post #110

Earlier quoted context omitted.

One thing that bothers me about this generation is this thirst for infinite punishment. People hunger for someone to blame, rattling off a long list of maladies that should befall that person, until they have been thoroughly satisfied, but they are never satisfied. They always feel there should be someone else, something more, something deserved . The truth is, there is no point to such a punishment here. It is unlik…

The news that I'm hearing now is that Boeing has been working on a software fix for this problem since at least January . Where were the glaring safety warnings to the airlines, their customers?

The thing about a software fix is that you never know when the solution is near. It could be fixed next week, or it may require an entire rewrite of critical systems. You just don't know until it's fully diagnosed. So why sound the alarm when plenty of flights have gone without problems and a software fix might be around the corner, especially if you have all your best men working on the problem?

Re: Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

#262

Post by js2 »

rocqua wrote: post #202
js2 wrote: post #119

Earlier quoted context omitted.

The runaway stabilizer trim procedure is how it was expected to be handled: https://www.flightglobal.com/news/articles/faa-order-tells-h... https://www.youtube.com/watch?v=3pPRuFHR1co The specifics of MCAS weren't out there because Boeing expected the pre-existing procedure to have been sufficient. That procedure wasn't sufficient, or the Lion and Ethiopian Air pilots were somehow not aware of it, or they forgot thei…

> The specifics of MCAS weren't out there because Boeing expected the pre-existing procedure to have been sufficient. This was argued by Boeing to the FAA, who accepted the reasoning. It should be noted that, if it had been determined the pre-existing procedure wasn't sufficient, then all pilots on the 737 Max would've had to undergo re-training. This would have been expensive, and probably hurt adoption of the new a…

> This would have been expensive, and probably hurt adoption of the new airframe.

What alternative did the airlines have though? The A320neo? Cause that would've required re-training too.

Probably Boeing should've pushed back against the airlines: we've made you a more fuel efficient 737, but it's going to require re-training.

Someone or someones may have thought: "MCAS is the only thing that requires retraining? Can't we fudge that?"

And the thing is, it still seems like MCAS is a reasonable solution, if poorly implemented.

Re: Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

#264

Post by ashelmire »

magduf wrote: post #254
ashelmire wrote: post #248

Earlier quoted context omitted.

Engineers don't make decisions like this. Not providing documentation of the feature or providing training to pilots was the problem, and it's caused by multiple management failures. The lack of sensor redundancy likely also is due to management.

The lack of sensor redundancy HAD to be signed off by a professional engineer. It doesn't matter if management pushed it; it's the engineer's (PE's) responsibility to refuse to sign off on it.

I’m not convinced sensor redundancy is the issue. The plane has two sensors; for some reason, however, the package that includes the AoA disagreement light costs extra.

It seems that lack of training and documentation was the reason these planes crashed though. The pilots didn’t know how to recognize the issue or resolve it.

Re: Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

#265

Post by cmurf »

CivBase wrote: post #233
proaralyst wrote: post #230

Earlier quoted context omitted.

Given the system assumed it was in stall, which means loss of altitude anyway, surely it's safer in general to go nose-down to avoid the stall? At least then you have a chance of recovery, which you don't in a stall. (Except of course, going nose-down.)

If you don't have enough altitude to afford going nose-down, let the pilot handle it. If your system can't come up with a safe solution, do not override the pilot's controls in favor of a dangerous solution. A computer should never assume it knows better than a pilot. A computer is only as good as the data it gets and the software it runs. Sensors fail. Data gets corrupted. In the current state of the industry, softw…

Elsewhere I've read MCAS does take altitude into account, as well as flaps, i.e. it's only active above a certain altitude, and only when flaps are retracted. So... yeah, we don't have the full story. And also in another thread, it's reported from the flight prior to Lion Air 610 (same plane) there were airspeed and altitude disagreements. I'm not at all clear from available reporting whether airspeed, altitude, and angle of attack were inconsistent, if that was a source of either autopilot confusion, and then pilot confusion, whether pilots did set stabilizer trim to cutoff and when and whether it was too late.

I'm a pilot (former CFII) and the whole automation fail danger strikes me as terrible. John Q Public says "I want the automation to override the pilot's mistakes!" What? OK fine. What about Asiana Airlines Flight 214 where the pilot advanced throttles, an explicit intent input, and yet autothrottles were set so the automation said nope. And then John Q Public are all, well the pilot should have KNOWN!

It's like it's a game where the pilot is only there as the last resort to be blamed if they too fail, even after a sequence of automation failures. Automation betraying pilots at low altitude is in my view functionally equivalent to an in-flight breakup. And automation in the cockpit mentality in the face of failures has been, for 20+years, "add another button, add another feature, add another routine" to tack on all the others.

And yes this absolutely makes me think of autonomous driving as total b.s. Airplanes are in a standardized system, with far bigger budgets for automation and yet we still have to fall back to human pilots for routine procedures like parking, taxiing, VFR approaches and landings, and telling the automation literally every detail it needs to do, ATC communication. It's ripe for end to end automation and yet we still don't do that. Driving cars is wildly more complicated for automation: non-standard streets, paint, signage, laws, pedestrian behavior, bicycles, cars still driven by humans, weather - haha. Sounds nice, great idea, keep trying, but it's complete bullshit.

Re: Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

#266

Post by WalterBright »

dingaling wrote: post #204
cjbprime wrote: post #170

Earlier quoted context omitted.

There's already two AoA vanes mandatory on every plane (even non-MAX planes). There is a warning if they disagree in the optional package that the North American airlines bought, but not any other airlines. The warning is not much of a warning, just a disagree light. It would have been impossible for the Lion Air pilots to benefit from this disagree light, because they didn't know that it was hooked up to a control s…

> There's already two AoA vanes mandatory on every plane And all Airbus types have three or four. Boeings only have two, even on the 787 ( on which one is vulnerable to damage from jetbridges ). It is disappointing that a manufacturer would cut corners on sensors for a $100 million aircraft.

Airbus needs more because there's no mechanical backup to the flight control computers.

Re: Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

#267

Post by daveslash »

magduf wrote: post #238
inferiorhuman wrote: post #194

Earlier quoted context omitted.

MCAS is designed to work only with autopilot disengaged. With autopilot and autothrottle engaged there would be similar logic at play because the general goal would be to not have the automation induce a stall. With everything disabled there is a risk that applying full throttle will result in the airplane pitching up dramatically beyond the ability of the elevator to pitch the airplane back down and potentially indu…

Boeing was right not to document anything, because then they might have to get a new certification (which is very expensive) for the plane, and pilots would need more training, which would make it hard or impossible for them to sell this plane to airlines as "just another 737". Remember, a few fatal crashes are worth it as long as it means higher corporate profits.

I think I saw that movie. "Fight Club"? Or was this the less well known sequel, "FLIGHT Club"?

Re: Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

#268

Post by jnbiche »

dang wrote: post #101
jnbiche wrote: post #35

Earlier quoted context omitted.

Here again. Downvotes for someone asking a bona fide question. Place has changed. It's a shame. Downvote away...

Would you please not break the site guidelines like this? Assuming you're right, making HN worse still is no way to go. https://news.ycombinator.com/newsguidelines.html

Ironically, I almost never got saw your above request because...your comment above was collapsed from the downvotes, even as I perused my own "threads". For some masochistic reason, I clicked the "+2" link from a comment almost two weeks ago, and ... there was your comment and request. It's fairly lucky I saw it at all.

So yes, I will try not to break the site guidelines again (I agree this is a clear case of breaking site guidelines). It just makes me sad how HN used to be a place where people could ask genuine questions and not be downvoted to invisibility, for whatever reason.

Re: Pilot Who Hitched a Ride Saved Lion Air 737 on the Day Before Deadly Crash

#269

Post by recursosamazoni »

inferiorhuman wrote: post #194
StavrosK wrote: post #188

Earlier quoted context omitted.

My question is why doesn't the "omg something is seriously fucked up give me manual control NOW" button disable the MCAS as well? That seems like a UX failure.

MCAS is designed to work only with autopilot disengaged. With autopilot and autothrottle engaged there would be similar logic at play because the general goal would be to not have the automation induce a stall. With everything disabled there is a risk that applying full throttle will result in the airplane pitching up dramatically beyond the ability of the elevator to pitch the airplane back down and potentially indu…

Thank you for your post. I've read that Boeing removed the "yoke jerk" function on the 737 MAX. The flight 302 PIC might have been trying to use it and I have not read whether that functional change was clearly explained to pilots. Many commentators don't seem to realize the extreme low altitude at which this particular struggle was occurring.
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