Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

E.U.’s Biggest Economies Ban Boeing Max 8 Jets

nytimes.com

Post reply on HN
Print view View original

301–310 of 365 posts

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#301

Post by mrdodge »

balls187 wrote: post #289
mrdodge wrote: post #152

Earlier quoted context omitted.

Those were produced pre-FAANG, Boeing probably paid comparatively better then. Do the smartest software engineers flock to Boeing in 2019? I think the relatively low pay and status of software engineers outside of the Bay Area is a huge risk to society. We are going to start seeing it show up in interesting places.

Pay is based on market forces, of which, skill is only one factor. In comparison German Engineers are not paid very well, so do you assume they are lesser skilled than US engineers? [1] 1: https://www.payscale.com/research/DE/Job=Software_Engineer/S... https://news.ycombinator.com/news

A lot of the good German engineers are in the US.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#302

Post by balls187 »

mrdodge wrote: post #301
balls187 wrote: post #289

Earlier quoted context omitted.

Pay is based on market forces, of which, skill is only one factor. In comparison German Engineers are not paid very well, so do you assume they are lesser skilled than US engineers? [1] 1: https://www.payscale.com/research/DE/Job=Software_Engineer/S... https://news.ycombinator.com/news

A lot of the good German engineers are in the US.

And a lot of great ones are in Germany.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#303

Post by linuxftw »

outworlder wrote: post #176
anaphor wrote: post #5

Earlier quoted context omitted.

The engines are larger than previous models and had to be moved forward, which causes it to (potentially) stall, so they implemented an anti-stalling mechanism called MCAS which relies on a particular sensor, which can malfunction potentially. They also didn't inform pilots that this system even existed which means they have trouble diagnosing the problem and will potentially only make it worse by trying other things…

Minor nitpick. It's not that the engines directly cause stalls(EDIT: of course if you pitch up too much you will stall at some point). Is that they can cause some unintended lift in some flight configurations. So MCAS is supposed to pitch down (by trimming) to keep the attitude under control Boeing's main argument is that the procedure for dealing with runaway trim is completely unchanged compared to other planes, so…

Maybe. Or perhaps a pilot disengages the system and stalls the plane.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#304

Post by StreamBright »

AWildC182 wrote: post #219
sfilargi wrote: post #146

I urge people to read the discussion by pilots regarding the 737 MAX. https://www.airlinepilotforums.com/safety/120514-ethiopian-7... It all comes down to this: "There are far too many aerodynamic bandaids that are permitted to pass the current standards. Not just this particular airplane, but a whole bunch of airframes. If the basic aerodynamics won't pass without the pushers, pullers and now AOA induced changes to…

It's a bit more complicated than that even. The 737 was originally designed for a very different mission than it's being used for right now. If you find pictures of the original 737-200s they look very different from the MAX line of today. It was built in an era when it was assumed that 707 and soon after 747 class airliners would serve the hubs and then smaller 737s would serve the small regional airports. As such t…

Are you saying that the lack of proper response to changed requirements is the primary source of 737MAX's issues?

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#305

Post by metanoia »

erokar wrote: post #253
dukoid wrote: post #247

Earlier quoted context omitted.

When I see cockpit videos, the pilots tell each other what they do / run checklists together... Does the MCAS do the same, i.e. announce "stall risk detected, increasing stabilizer trim by 2.5 degree to xx degree"?

No, but the pilots will hear/see the trim wheel moving.

Inattention to autopilot modes has killed before. So much focus is put on pilots recognizing and confirming flight mode annunciator mode changes (such as change of autopilot or autothrottle state) has been put into place to stop that kind of accident.

The lack of feedback from the MCAS system is probably the killer here.

How am I supposed to know that MCAS is operating, and how do I know when to hit trim cutoff switches to override it? You don't want to ever be asking "what the heck is the airplane doing now?". Watching the trim wheel to check if it's spinning nose down all the time isn't going to work.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#306

Post by StreamBright »

sandworm101 wrote: post #283
namirez wrote: post #281

Earlier quoted context omitted.

Fly-by-wire means the control surface actuators are connected to cockpit controls electronically rather than with hydraulic lines or metal cables; it's not necessarily related to stability and control augmentation system. With regard to the other point, I don't think anyone is advocating for very high aerodynamic stability. That would be a B52 carrying nuclear weapons. It was designed to be extremely stable and forgi…

Yes it would. There are backup systems to keep things working even with both engines dry (ram air turbine etc). In fact, if you really want to stretch our a glide, all those automated systems are probably a good things. They will keep the aircraft more perfectly trimmed for a glide than the pilots ever could by hand. https://en.wikipedia.org/wiki/Ram_air_turbine

And in case of the electrical system being down how do you control the flight when you have fly by wire controls?

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#307

Post by linuxftw »

outworlder wrote: post #201
w0utert wrote: post #54

Earlier quoted context omitted.

It sounds really stupid for Boeing if you put it that way. I can imagine it looks good on the marketing material, 'no pilot retraining required!', but as far as I understand from all the analysis so far, it's actually not that hard to disable the new MCAS system and prevent a crash. As a pilot you only need to know it is there, and what happens if it somehow fails. I would be surprised if they had sold even a single…

> As a pilot you only need to know it is there, and what happens if it somehow fails. You don't even have to know it is there. All you need to know is "hey, auto trim is acting very funky today and I'm having to fight it. Better override.". And hit two switches. > I would be surprised if they had sold even a single plane less if they advertised it as 'very minimal pilot retraining necessary'. They were likely afraid…

> All you need to know is "hey, auto trim is acting very funky today and I'm having to fight it. Better override."

Unless you believe your instruments (AoA reading high) and assume the plane is actually doing the correct thing.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#308

Post by rocqua »

AWildC182 wrote: post #284
edoloughlin wrote: post #279

Earlier quoted context omitted.

such airframes induce more drag and burn more fuel As a curious bystander, I assumed using fly by wire tech to achieve stability would involve using control surfaces, which increase drag by their nature. How would an airframe that's naturally stable and doesn't require control inputs burn more fuel?

It's more about preventing a stall with a swept wing which is needed to achieve high mach numbers. That said, an easy (but different) case to visualize is a traditional tailplane. The center of gravity on an airplane is in front of the wing so it wants to pitch down slowly. The tail pushes DOWN in the back to keep the nose up. Nose heavy planes are stable and forgiving but you induce drag because the wing needs to su…

So the stable airframes we know are stable because a dynamic aerodynamic force opposes a static one.

Makes sense then, that those opposing aerodynamic forces induce drag.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#309

Post by linuxftw »

sandworm101 wrote: post #4
Areading314 wrote: post #3

Does anyone actually know or suspect what's wrong with these planes? Hardware issue? Software issue?

All three. It also has to do with pilot training. The general idea is that there is an auto-trim system meant to stop the plane from stalling. But when it gets bad data from a faulty sensor it tries to crash the aircraft (short version). Pilots, all pilots, are trained to recognize this and override the system, but this aircraft requires them to do some things slightly differently. Specifically, they have to shut dow…

How do we know the software works in all conditions, as described?

We don't know it had anything to do with pilot training until the investigation is actually finished. To say it's pilot training is pushing Boeing's narrative.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#310

Post by paulmd »

jakelarkin wrote: post #264
sfilargi wrote: post #146

I urge people to read the discussion by pilots regarding the 737 MAX. https://www.airlinepilotforums.com/safety/120514-ethiopian-7... It all comes down to this: "There are far too many aerodynamic bandaids that are permitted to pass the current standards. Not just this particular airplane, but a whole bunch of airframes. If the basic aerodynamics won't pass without the pushers, pullers and now AOA induced changes to…

"the plane should never have gotten the green light to fly." this is an overstatement. airframe fuel efficiency is a undoubtable good thing vis a vis climate change, costs, etc. Obviously they've reached a point were the aerodynamic profile of a modern, efficient airframe is difficult to control via manual pilot input alone in some scenarios. This was the case for stealth technology with fighter/bomber designs.. the…

The problem here isn't that a 737 MAX style design is inherently unstable. The issue is that the larger engines really needed longer landing gear and other significant airframe changes, but due to demands from Southwest that it remain within type-certification for the 737 (to avoid the costs of pilot retraining) some unfortunate compromises were made that affected the aircraft's behavior.

You can design an aircraft just like this that won't have those characteristics. You'll just need to pay to get it certified and then airlines will have to pay to train their pilots. Instead, Southwest wanted the band-aid fix, and Boeing obliged them.

Post reply on HN