Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS • Hacker News Board

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#181

Post by kortilla » Sun, May 12, 2019, 4:08 AM UTC

CydeWeys wrote: post #109

cm2187 wrote: post #95

Earlier quoted context omitted.

I think the point if the OP isn't that a new design would have the same flaw, but rather that it would possibly introduce many other flaws. I think the analogy to a full software rewrite vs fixing a bug in a battle tested software is relevant.

The larger point is that the 737 is a highly antiquated design by this point. The cockpit has screens that emulate old analog displays to maintain common type rating, even though much better ways of displaying that data now exist. The plane's controls are highly manual, which are a negative now that fly-by-wire and autopilots are mature and very good. Hell, the entire plane sits so low to the ground because it was de…

>so low to the ground because it was designed to support a non-jetway use case (which is now non-existent)

Complete bullshit. I’ve boarded/deplaned without a jetway in Beijing, SLC, JAC, and AMS in the last couple of years alone.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#182

Post by kuzehanka » Sun, May 12, 2019, 4:14 AM UTC

kortilla wrote: post #138

JudgeWapner wrote: post #111

Earlier quoted context omitted.

> The engine mounting certainly does not make the plane unsafe. I don't think this is a very...'precise' statement. what is "safe" in the context of aviation? If you had no MCAS, then this plane has a very bad propensity to stall . I hope we can both agree that's an unsafe airplane. You can't just say "don't do that [pull up too much] and then you're fine". The aircraft "wants" to pitch up too high and stall, which p…

No, it did not “have a bad propensity to stall”. That’s a very imprecise statement in the first place but if you take it to mean, it would try to stall during normal flight conditions, it’s definitely false. Airbus aircraft are “safe” despite the fact that dual conflicting pilot input is averaged without stick feedback (see the Airfrance flight from Brazil). If electronics being used to fly the aircraft upsets you, y…

So much ignorance and misinformation about this issue even on HN.

The parent comment and entire thread is 100% correct. There is nothing inherently unstable or unsafe about the MAX 8. It has a pitch-up characteristic that's mild compared to some other commercial jets like the 757.

The only reason MCAS was put on that plane was to allow the MAX 8 to share a type rating with the rest of the 737 family, to make it so that it handles like any other 737 despite the pitch-up characteristic.

Go ask any commercial pilot, go watch any of the commercial pilots on youtube who have commented on this, go look on stackexchange. The notion that the MAX 8 is inherently unstable, or unsound, or dangerous, is a laughable myth to anyone in the industry. I get that the news cycle is financially rewarded for fearmongering, but I really expected people who frequent HN to know better and do some cursory research into the topic rather than posting comments that perpetuate bullshit.

There are several major issues with what boeing has done, such as the alleged failure to reclassify MCAS as a critical system after flight testing. But instead of discussing these legitimate issues, public debate seems to have been directed towards a bullshit myth about the airframe being inherently unstable. This has been eye-opening and dispelled my notion that HN had above-average quality of discussion on technical topics.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#183

Post by mannykannot » Sun, May 12, 2019, 4:15 AM UTC

Obi_Juan_Kenobi wrote: post #130

cletus wrote: post #118

So a lot is known at this point: 1. The A320neo caught Boeing completely off-guard; 2. The threat of the likes of American Airlines (already a mixed Airbus/Boeing customer and the largest airline in the world) placing a large A320neo order for regional aircraft operations scared the bejesus out of Boeing management; 3. For airlines like Southwest that are pure 737, the prospect of adding a plane that didn't share a c…

> These engines moving made the plane more vulnerable to a stall situation. I don't think this is correct. A lot is being made about the engine move with regard to aerodynamic behavior, but it doesn't seem at all outside of the bounds of what is considered standard. Pilots report that a similar 'light stick feel' at high AoA is already present in aircraft like the 757. It's not that the aerodynamic change was worse o…

> It's not that the aerodynamic change was worse or better...

Having the control get 'lighter' (more sensitive to increased back-force) as one approaches the stall is definitely an undesirable characteristic, as it increases the risk of a distracted pilot stalling. While a change in the opposite direction might have been problematic (insofar as additional training is a problem), the way it actually goes is more likely to prompt the FAA to require something be done about it.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#184

Post by logjammin » Sun, May 12, 2019, 4:23 AM UTC

old-gregg wrote: post #65

erentz wrote: post #43

Earlier quoted context omitted.

> What is the endgame now for 737 MAX planes? The bugs will be addressed and they'll still fly. Airlines have no choice, there's a limited capacity in the world for airplane construction, several thousands of orders on the books for the 737 and 320 waiting to be filled. What can an airline do? They can cut back some orders but not all orders. > I'd honestly like to see the 737 MAX taken out of service and Boeing simp…

> The bugs will be addressed and they'll still fly. The engines are mounted incorrectly, so much so that Boeing believed pilots need the assistance of MCAS on take-off now. The bug isn't with its algorithms, rather the need for MCAS to begin with. They can't "address" it. That's why I'll be very careful not to ever book a flight on a 737 Max, probably easier to simply stick to Airbus-only airlines: Jetblue, Alaska/Vi…

Alaska was, before they bought Virgin, famously a Boeing-only airline! (And a 737-only airline at that!)

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#185

Post by JudgeWapner » Sun, May 12, 2019, 5:00 AM UTC

kuzehanka wrote: post #182

kortilla wrote: post #138

Earlier quoted context omitted.

No, it did not “have a bad propensity to stall”. That’s a very imprecise statement in the first place but if you take it to mean, it would try to stall during normal flight conditions, it’s definitely false. Airbus aircraft are “safe” despite the fact that dual conflicting pilot input is averaged without stick feedback (see the Airfrance flight from Brazil). If electronics being used to fly the aircraft upsets you, y…

So much ignorance and misinformation about this issue even on HN. The parent comment and entire thread is 100% correct. There is nothing inherently unstable or unsafe about the MAX 8. It has a pitch-up characteristic that's mild compared to some other commercial jets like the 757. The only reason MCAS was put on that plane was to allow the MAX 8 to share a type rating with the rest of the 737 family, to make it so th…

you're concerned about "comments that perpetuate bullshit". To me, the real bullshit is that a computer drove 2 aircraft into the earth. If we're so mistaken about what happened here, maybe the boeing engineers are similarly mistaken about how flight control systems work. I think they're the ones who have "ignorance and misinformation", like how many AoA sensors are required. Or whether a vigorous elevator UP position from the stick should be ignored and in fact counteracted by an opposite stabilizer position. Tell me what perpetuates the arrogance in the software departments at boeing that the computer knows better than the human. Unlike the pilots, the computer has nothing to lose. Yet the computer won the final decision. But calling this out is just the "news cycle financially rewarding" ... something ?

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#186

Post by ummonk » Sun, May 12, 2019, 5:35 AM UTC

hirowan wrote: post #98

cm2187 wrote: post #94

Earlier quoted context omitted.

A brand new design would probably introduce more serious flaws than an interation of a mature design, so I am not sure it would be safer. In term of public perception, it is a PR disaster but not unprecedented. The DC-10 went through a similar rocky start where passengers just wouldn't want to board it. But after the flaws were fixed it turned out to be quite reliable.

> A brand new design would probably introduce more serious flaws than an interation of a mature design As evidenced by the ever-crashing 787s and A350s.

The 787 was rushed through as well with the same modern Boeing safety culture and we were merely lucky that none of the flaws discovered in the 787 were bad enough to cause fatal accidents before they were rectified. Read up on its battery issues if you want an idea of what could have gone wrong.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#187

Post by erichocean » Sun, May 12, 2019, 5:38 AM UTC

TomVDB wrote: post #180

erichocean wrote: post #149

Earlier quoted context omitted.

> Gotta love deregulation. I dunno, I see it as the opposite: regulation (apparently) made it impossible to just train pilots on this one new feature, instead requiring a full recertification of both the airframe and the pilots, which is incredibly expensive and unnecessary relative to what was actually required to save lives. So one way of looking at is is: regulation caused perverse incentives that ultimately got p…

A different way to look at this is: does this particular perverse incentive justify reduced regulation so that it can’t happen anymore. Even if your assessment is valid, you’d likely be throwing away the baby with the bath water if you’d cut regulation to avoid it.

I would think it would justify additional regulations to allow for something like "upgrades" to existing certifications instead of the binary (full recertification|pretend plane is identical) standard we appear to have today that resulted in the 737 Max tragedy.

Is that less regulation? More regulation? I don't know, and I doubt it matters if it's "less" or "more" since the goal is fewer dead people, not passing an ideological Turing test.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#188

Post by inferiorhuman » Sun, May 12, 2019, 5:44 AM UTC

kuzehanka wrote: post #182

kortilla wrote: post #138

Earlier quoted context omitted.

No, it did not “have a bad propensity to stall”. That’s a very imprecise statement in the first place but if you take it to mean, it would try to stall during normal flight conditions, it’s definitely false. Airbus aircraft are “safe” despite the fact that dual conflicting pilot input is averaged without stick feedback (see the Airfrance flight from Brazil). If electronics being used to fly the aircraft upsets you, y…

So much ignorance and misinformation about this issue even on HN. The parent comment and entire thread is 100% correct. There is nothing inherently unstable or unsafe about the MAX 8. It has a pitch-up characteristic that's mild compared to some other commercial jets like the 757. The only reason MCAS was put on that plane was to allow the MAX 8 to share a type rating with the rest of the 737 family, to make it so th…

It has a pitch-up characteristic that's mild compared to some other commercial jets like the 757.

Do you have any personal experience with or references for this claim?

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#189

Post by ummonk » Sun, May 12, 2019, 5:46 AM UTC

deskamess wrote: post #57

erentz wrote: post #32

Earlier quoted context omitted.

Had Boeing built the 737 at the time Airbus built the A320 they would've had a taller undercarriage also. For example the narrow body 757 built around the time of the A320 does have this. When the 737 was built back in the 60s it was intended to be a small regional jet, not the continent and ocean crossing aircraft it evolved into over the years since. It originally came with a retractable staircase for passengers to…

Why would they not have gone with a, say, 757 MAX - it seems to fit the bill spec wise. Is it that global pilot pool is not as great for the 757 as 737?

The 757 is a larger jet. Smaller jets have become increasingly popular with airlines. Probably had to do with the flexibility and extra timing / route options to offer by flying lots of small planes vs fewer large planes.

Also, global pilot pool doesn’t matter as much as what individual aurlines’ pilots are certified on. The specific airlines that operate 737s would prefer not to have to retrain their pilots on a new aircraft; if they had to retrain them for the 757max that would open the door to consider the airbus as an equally good option.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#190

Post by btgeekboy » Sun, May 12, 2019, 5:52 AM UTC

djsumdog wrote: post #28

What is the endgame now for 737 MAX planes? Every airline using them has had several weeks to totally reorganize to deal with these huge missing parts of their fleets. Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and…

> Boeing keeps talking about fixing them and putting them back in the air, but I dunno.

More than that - they're continuing to manufacture them. There's quite a few of them stacked up at KPAE, just sitting there waiting for their software updates, all painted in customer livery. (They're not even manufactured at PAE; they're ferried there for storage.)