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Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

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Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#171

Post by kevinmgranger »

umvi wrote: post #81
blakesterz wrote: post #4

"Dutch Roll is a coupled out of phase movement of the aircraft as result of weakened directional stability (provided by the vertical tail and rudder), in which the aircraft oscillates around its vertical as well as longitudinal axis (coupled yaw and roll)." That sounds pretty scary. I wonder why it wasn't bigger news when it happened last month?

Not as scary as flying upside down which is what I originally thought based on title alone. Most people are familiar with "barrel roll" but by comparison this just looks like wiggling. Counterintuitively though my understanding is that barrel rolls are generally safe even for large planes since it's a stable 1G maneuver (some jock irresponsible air force pilot used to regularly barrel roll B-52s until he did one too…

A barrel roll or an aileron roll? Most people call an aileron roll a barrel roll (no thanks to Star Fox)

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#172

Post by kstrauser »

zh3 wrote: post #148
umvi wrote: post #81

Earlier quoted context omitted.

Not as scary as flying upside down which is what I originally thought based on title alone. Most people are familiar with "barrel roll" but by comparison this just looks like wiggling. Counterintuitively though my understanding is that barrel rolls are generally safe even for large planes since it's a stable 1G maneuver (some jock irresponsible air force pilot used to regularly barrel roll B-52s until he did one too…

Probably wasn't a B52. Tex Johnston was reknowned for barrel rolling a 707 during a demo back in the day - there's grainy video of it on youtube. Apparently the Boing execs at the demo didn't know it was going to happen and nearly had heart attacks when he did. Video on youtube: https://www.youtube.com/watch?v=iz1Eze3QrDU

Tex flew in cowboy boots and, well, was named Tex. I don’t know what they thought would happen.

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#173

Post by alistairSH »

exabrial wrote: post #107

What the news about Boeing has done is make me pay more attention to commercial aviation in general. The number of aviation incidents is actually pretty crazy, and no, Boeing is not at the center of them despite what the media would have you believe. What is amazing though is the actual injury and fatality rate is really low due to well trained crews and measured responses by air controllers.

What really blows my mind in the number of near-misses on active runways (at least within the US). I don't know if the trend is up, as I don't have historic data, but certainly looking at Youtube (VASAviation, etc), there are a scary number of them (2 within the last 45 days at one of my local airports).

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#174

Post by kstrauser »

jader201 wrote: post #87
tjpnz wrote: post #20

Earlier quoted context omitted.

Here's a video demonstrating it: https://youtu.be/Zmjam1evDD4

I feel like “roll” is a bad word for what’s happening here. In my brain, when I hear “roll”, I’m thinking a 360 degree rotation in either the vertical or horizontal axis (or both). This is far from that (even in the real life footage linked in the sibling comments). This is more like a “Dutch wobble” or “tilt”. But I’m not an aviator, so what do I know.

In any case, it sure beats a Dutch crunch.

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#175

Post by RobotToaster »

pfannkuchen wrote: post #134
FabHK wrote: post #127

Earlier quoted context omitted.

> they simply did not like this particular plane. …and employed a face-saving (though probably very expensive) way of communicating it.

I suspect the face saving culture is holding China back significantly since it adds a ton of noise to interpersonal signal propagation. I wonder if the government is doing anything social engineering-y to try to reduce it?

> I wonder if the government is doing anything social engineering-y to try to reduce it?

I know Xi Jinping launching an anti-corruption program was considered a pretty big deal, because it meant admitting that corruption exists in the CPC.

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#176

Post by lastofthemojito »

impulser_ wrote: post #145
amarant wrote: post #25

It kinda bothers me that airlines are still placing orders for new Boeing airplanes. Taking delivery of old orders is one thing, since they can't really back out of those, but placing new orders implies that some level of trust remains for this company, and I just don't see how that makes any sense at all?

The Max 8 are great planes. I rode one recently, in fact it was with Southwest, it was probably the best plane I flown in. Lots of space, comfortable and quiet. They just need to fix the bad part issues they seem to have. Personally, I would fly on a Max 8 again.

Looking at Southwest is probably a good way to put the Boeing issues in perspective. It's easy to want to freak out over the negative headlines over the past few years, and the MCAS fiasco is a well-deserved black mark on Boeing's reputation.

But again, looking at bigger perspective, Southwest Airlines operates an all-Boeing fleet of 800+ airlines doing 4000+ flights per day. About a million and a half flights per year. And in their 50+ years of operation, there have been 4 deaths associated with Southwest flights, 1 of which was a suicide where a guy walked onto a runway and another was an unruly passenger who tried to storm a cockpit.

I don't want to let Boeing off the hook - their recent cock-ups absolutely seem to indicate cultural problems that need to be fixed so that quality can improve rather than continue to slide. But honestly, getting on a 737 Max to go on a trip still seems way safer than hopping on the highway.

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#177

Post by RobotToaster »

jgalt212 wrote: post #165
pfannkuchen wrote: post #134

Earlier quoted context omitted.

I suspect the face saving culture is holding China back significantly since it adds a ton of noise to interpersonal signal propagation. I wonder if the government is doing anything social engineering-y to try to reduce it?

seriously. Look at the Kardashians. They turned every embarrassing event into a money making opportunity.

You think the Kardashians are a good model for government?

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#178

Post by ceejayoz »

mlcrypto wrote: post #164
dboreham wrote: post #115

Earlier quoted context omitted.

Statistically it is not. Most of the time travellers don't know if they're on an Airbus or Boeing aircraft and hardly ever figure out that it's a MAX.

Infinite loss multiplied by small chance is still infinite risk

What daily activities don't have a small chance of the same risk?

Eating has a small chance of choking to death. Walking has a small chance of getting hit by a falling tree branch. Pooping has a small chance of causing a brain aneurysm to pop.

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#179

Post by whymauri »

alistairSH wrote: post #173
exabrial wrote: post #107

What the news about Boeing has done is make me pay more attention to commercial aviation in general. The number of aviation incidents is actually pretty crazy, and no, Boeing is not at the center of them despite what the media would have you believe. What is amazing though is the actual injury and fatality rate is really low due to well trained crews and measured responses by air controllers.

What really blows my mind in the number of near-misses on active runways (at least within the US). I don't know if the trend is up, as I don't have historic data, but certainly looking at Youtube (VASAviation, etc), there are a scary number of them (2 within the last 45 days at one of my local airports).

I watched this video recently and found it really informative w.r.t. commercial aviation near misses:

https://www.youtube.com/watch?v=mIiPt1YVkP8

It gives just enough detail around the classification system, rate of incidents, root causes, etc, that I could search for and learn more on my own after.

Re: Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

#180

Post by tekla »

zthrowaway wrote: post #154
tekla wrote: post #102

I'm going to to laugh at the bad takes on this thread, and await a more accurate report. Dutch roll is undesirable, but its a basic consequence of some converging aeronautical effects.

Yes but the alarming thing here is the damaged PCU...

Sure. but that's just like, OK, that by itself means very little.

It could mean the standby PCU somehow activated by itself, maybe damage causing a un-commanded activation, maybe software bug, maybe God said fuck this plane in particular.

The point is we have no idea since there are not enough details to know. But of course, on HN we have a army of people who think they know stuff because Wikipedia.

https://trends.google.com/trends/explore?q=dutch%20roll&date...

Yep, exactly what I suspected.

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