Canada grounds Boeing 737 Max 8 • Hacker News Board

Re: Canada grounds Boeing 737 Max 8

#221

Post by breck » Wed, Mar 13, 2019, 6:14 PM UTC

erokar wrote: post #160

If this Reddit comment is true it's pretty damning. https://www.reddit.com/r/flying/comments/b08h03/737_max_mega... Claims intermittent fluctuations in AoA can activate the MCAS. So no need for the AoA indicator to be faulty then, means the risk of falsa MCAS intervention higher than previously believed.

I'd bet against that rumor with 50 to 1 odds.

If there really was such a memo going around Boeing that would certainly be leaked. The leaker would probably due so publicly as well, as they would literally save lives and easily be free from retribution.

Re: Canada grounds Boeing 737 Max 8

#222

Post by rootusrootus » Wed, Mar 13, 2019, 6:15 PM UTC

mzs wrote: post #180

helaoban wrote: post #153

Earlier quoted context omitted.

Quote: "I covered airline safety and the FAA for four years, and I cannot remember a time when the FAA was so alone among world regulators on a serious safety issue. " Neither viewpoint is supported here. The anomaly is that there is a disagreement between the FAA and the other aviation authorities, but no evidence has yet surfaced that would vindicate either party.

at least quote it all please, "When a major accident like this happened, global aviation authorities conferred with the FAA -- which took the lead."

Maybe this is a reflection of the recent loss of respect the U.S. has been facing in the last couple years. Other countries are feeling less inclined to defer to our judgement.

Re: Canada grounds Boeing 737 Max 8

#223

Post by nraynaud » Wed, Mar 13, 2019, 6:18 PM UTC

js2 wrote: post #20

Having read many commments on HN and elsewhere since the crash, I know I’m in the minority here when I say this but to me it seems like the US airlines and FAA are following their procedures, the same procedures that make the US airlines the safest in the world, while the rest of the world is, I don’t quite want to use the word panicking, but at least giving into pressure from people who aren’t aviation safety expert…

I didn't see any comment that countered the narrative that the 2 planes that crashed had an erratic altitude before crashing.

We have a natural and simple scenario to explain both, and a serious reason to suspect that any left side angle of attack indicator could have a mishap because those things happen and it's normally not a big deal.

Even if the investigation deem that the root causes are different, it is the most natural explanation of those accidents absent more information, and it is even a nominal chain of event that was planned by Boeing.

Re: Canada grounds Boeing 737 Max 8

#224

Post by throwaway427 » Wed, Mar 13, 2019, 6:20 PM UTC

janj wrote: post #149

throwaway427 wrote: post #49

Earlier quoted context omitted.

I agree and I don't think you deserve the downvotes. The FAA is an institution with a deep sense of safety first and independence from (and even dominion over) private industry. They are also a body of experts, with more collective knowledge than any other similar body of domain experts in world. If we believe in institutions of experts who study and make recommendations regarding complex systems, we owe it to the FA…

It's interesting you put it this way. I just heard on NPR this morning that the FAA and NTSB is actually in partnership with private industry (like Boeing and the airlines) for cooperative self regulation because the FAA and NTSB just doesn't have the resources to provide adequate inspections without their help. I'll see if I can find that interview. https://www.npr.org/2019/03/13/702908761/why-did-a-boeing-73...

I listened to this interview and it's interesting the way you put it:

Steve Inskeep rephrases a statement that Goelz makes to make it seem like the FAA is short staffed and that airline compliance is on the honor system.

Goelz then says what he means is that there cannot be an independent FAA inspector in every single corner of a manufacturer or maintenance shop, but by then it's too late because the seed has been planted listeners mind.

So here you are saying the "FAA and NTSB just doesn't have the resources to provide adequate inspections" and that the overall compliance model here is "cooperative self regulation" which... I guess barring the FAA having a 1:1 staff for every employee in the airline industry we are indeed going to have "cooperative self regulation".

Re: Canada grounds Boeing 737 Max 8

#225

Post by xutopia » Wed, Mar 13, 2019, 6:20 PM UTC

breck wrote: post #221

erokar wrote: post #160

If this Reddit comment is true it's pretty damning. https://www.reddit.com/r/flying/comments/b08h03/737_max_mega... Claims intermittent fluctuations in AoA can activate the MCAS. So no need for the AoA indicator to be faulty then, means the risk of falsa MCAS intervention higher than previously believed.

I'd bet against that rumor with 50 to 1 odds. If there really was such a memo going around Boeing that would certainly be leaked. The leaker would probably due so publicly as well, as they would literally save lives and easily be free from retribution.

I'm willing to bet 100$ that it is true.

Re: Canada grounds Boeing 737 Max 8

#226

Post by TomMckenny » Wed, Mar 13, 2019, 6:21 PM UTC

yingw787 wrote: post #157

And then there was one. I do wonder if we can halt and revert the deterioration of the Civil Service before the whole "civilization is two days worth of food and water" scenario arrives. If it does, I think it'll be through something that generates a disproportionate amount of fear and anxiety in people resulting in a significant impact to the economy in a sector where middle to upper class folks are heavily exposed…

Also on the upside, we now have a list of countries that place more value on consumers than the US.

Re: Canada grounds Boeing 737 Max 8

#227

Post by a3n » Wed, Mar 13, 2019, 6:22 PM UTC

Scarbutt wrote: post #161

js2 wrote: post #59

Earlier quoted context omitted.

Another 737 Max crashing in the face of the current scrutiny would destroy it even worse, wouldn’t it? Is that just a calculated gamble?

Is that just a calculated gamble? Yes, because by now, every pilot still flying that plane has been trained to deal with the issue.

As were, I'm guessing, the Ethiopian pilots.

Re: Canada grounds Boeing 737 Max 8

#228

Post by danepowell » Wed, Mar 13, 2019, 6:23 PM UTC

js2 wrote: post #20

Having read many commments on HN and elsewhere since the crash, I know I’m in the minority here when I say this but to me it seems like the US airlines and FAA are following their procedures, the same procedures that make the US airlines the safest in the world, while the rest of the world is, I don’t quite want to use the word panicking, but at least giving into pressure from people who aren’t aviation safety expert…

I understand and agree that we don't want knee-jerk reactions on the part of regulators.

I'm only an aviation enthusiast and by no means an expert, and fully admit that I could be wrong, and even with my natural inclination to reserve judgement, to me it seems obvious that grounding is warranted purely from a statistic viewpoint.

Compare the release of the 737 MAX 8 with the release of other recent-ish models like the 777 and 787. It was 14 years before the 777 suffered even a single hull loss, and 20 years before a crash of the magnitude of the 737 MAX 8 (loss of all souls). The 787 is almost a decade old and has zero hull losses or fatalities.

The 737 MAX 8 is less than a few years old and already has two catastrophic crashes? I know that it's hard to draw too much information from just two data points, but that's pretty compelling to me.

Re: Canada grounds Boeing 737 Max 8

#229

Post by cmurf » Wed, Mar 13, 2019, 6:23 PM UTC

msbarnett wrote: post #75

elliekelly wrote: post #63

Earlier quoted context omitted.

My understanding is that it's a bit of both. This Slate article[1] described it as both a design flaw and an effort to paper over that design flaw by tweaking the autopilot system. >Boeing swapped out the engines for new models, which, together with airframe tweaks, promised a 20 percent increase in fuel efficiency. In order to accommodate the engine’s larger diameter, Boeing engineers had to move the point where the…

Yeah, my understanding is essentially, the changes made the Max 8 not behave aerodynamically like other 737s. This would normally mean that pilots would need to requalify on it as a new plane type, in order to legally fly one. But that's more expensive for Boeing's customers, so to make it more attractive, they decided to "paper over" the differences in behaviour with software. Fly it like any other 737, and if it st…

It's not the autotrim that you can't fight. The plane can be trimmed (elevator surface) in such a way that pilot yoke input (stabilizer surface) cannot fight against. That is common to all 737's, and all pilots know about it. It is not that the autotrim feature can't be fought.

What's new in the MAX is the autotrim doesn't terminate when the pilot gives back pressure on the yoke if MCAS senses high angle of attack, it will do an uncommanded nose down (every I think 10s). This is to compensate for the MAX engine nacelle which provides a meaningful amount of lift to cause a pitch up moment in high angles of attack, unlike previous 737's.

I wonder whether the stall behavior between 737's is slightly dissimilar or very dissimilar without MCAS, between 737NG and 737 MAX? And then quantifying that difference. I also seriously wonder if it's even slightly more likely for a pilot to induce a stall as a result of not knowing about the natural uncorrected stall behavior of the new design compared to previous designs. MCAS is not my concern, it's how the plane flies without it that I wonder about.

Also, WSJ is reporting that the MCAS software update mandated by the FAA in an airworthiness directive was delayed due to the nearly five week government shutdown. I'm already imagining the tweets...

Re: Canada grounds Boeing 737 Max 8

#230

Post by mises » Wed, Mar 13, 2019, 6:25 PM UTC

js2 wrote: post #20

Having read many commments on HN and elsewhere since the crash, I know I’m in the minority here when I say this but to me it seems like the US airlines and FAA are following their procedures, the same procedures that make the US airlines the safest in the world, while the rest of the world is, I don’t quite want to use the word panicking, but at least giving into pressure from people who aren’t aviation safety expert…

The thing people aren't looking at is the condition of the planes. Both crashes happened with planes of third-world nations, and might not have been held to the same rigorous standards. I'm glad America is trying to get the black box, because I'm not sure I'd trust the Ethiopian govt not to tamper with it just to protect their image (and their tourism industry).