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

Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll

avherald.com

Post reply on HN
Print view View original

191–200 of 240 posts

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

#191

Post by rootusrootus »

nabla9 wrote: post #139
senordevnyc wrote: post #52

Earlier quoted context omitted.

While true, this was a pretty different situation in that it was 1959 (engineering standards have changed a lot in the last 65 years), and the dutch rolls were being performed intentionally for demonstration purposes.

1985 the dedliest single aircraft accident was due to dutch roll. Japan Airlines Boeing 747SR. 2013 KC-135 Stratotanker broke up in flight due to dutch roll. 2005 Airbus A310 survived with serious structural damage.

Of those three examples, only the KC-135 was caused by the dutch roll. The other two were caused by structural failures, the dutch roll was incidental.

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

#192

Post by seanmcdirmid »

RobotToaster wrote: post #175
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?

> 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.

That isn’t true though. All presidents launch anti corruption campaigns to solidify their power when they start. Xi did it, Hu did it, Jiang did it, I bet Deng did it (although the office was merged yet, he was at least supreme leader). When they are all corrupt, it is easy to (a) clean house of people you don’t like (b) protect and promote your supporters and (c) scare lots of monkeys by killing lots of chickens.

The CPC always admitted there was corruption, to do otherwise would simply lose credibility with people. Given that Xi is now president for life, the corruption should simply be accumulating now since the 10 year house cleaning cycle has been broken.

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

#193

Post by jgalt212 »

RobotToaster wrote: post #177
jgalt212 wrote: post #165

Earlier quoted context omitted.

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?

Of course not. I meant it as an extreme counter-example.

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

#194

Post by jll29 »

brandall10 wrote: post #92
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?

Just flew a Max from Denver to Mexico City a couple days back. It was mostly uneventful, but as we were preparing to land the aircraft banked hard to the left and began to experience something akin to this...like it hit a sudden pocket of turbulence at the apex of the turn and began to pogo around. It was minor and far from inducing damage to the vehicle, but in that moment remembered where I was while clenching my b…

I hope nobody got hurt (assume so, you may have told you otherwise). Is this something pilots get trained for how to cope with this type of incident?

What happened to passengers (are they usually injured from things falling/flying around)?

Boeing is getting some bad news these days, but multiple whistle-blowers in a row is the worst.

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

#195

Post by kqr »

rollulus wrote: post #108

As a Dutchman the endless list of apparent “Dutch” things never ceases to surprise me. Uncles, courage, ovens, double, going, etc., and a new one to my list: rolls. And none of them means any good.

A Dutch book can be good depending on which side of it you are on!

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

#196

Post by [deleted] »

epolanski wrote: post #183
throwup238 wrote: post #78

Earlier quoted context omitted.

> 1) Even if the max had hiccups, plenty of them, it is an absolutely safe airplane by any measure. Except fatalities.

Even by fatalities. 737 Maxes have flown more than a couple of million of flights, at least, since they entered service, that puts their fatal incident rate at similar levels of the A320. The only two incidents, also, as you know, were related and both happened 5+ years ago.

[deleted]

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

#197

Post by shdon »

AnimalMuppet wrote: post #85
ragebol wrote: post #75

Earlier quoted context omitted.

Maybe the ice skaters took it from ships, also an old Dutch tradition I suppose.

I'm not sure if this is relevant, but: I have read that back in the day (1500s-1700s), the Dutch built flat-bottomed boats that could carry a lot, and the English built round-bottomed boats that handled better in the ocean. Maybe the way a Dutch boat handled in heavier seas is the origin of the term?

That was indeed my guess.

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

#198

Post by krisoft »

somenameforme wrote: post #189
krisoft wrote: post #110

Earlier quoted context omitted.

Okay. So let's compare accidents per flights to accidents per trip with bike/car. IATA reports 1.19 accidents per million flights in the 2019-2023 years. [1] Your turn to find a comparable number for road vehicles. 1: https://www.iata.org/en/pressroom/2024-releases/2024-02-28-0...

You pretty quickly shifted the goal posts there didn't you? That's for all flight vessels, not just Boeing's 737 class. You're also misreading your stats (that's per sector, not per million), but in either case I'm more interested in fatality rates. Your site gives a hull loss rate of 1 per 4.94 million flights for jets. For vehicles, the average person makes two trips a day over a total of 29.2 miles. [1] So we can…

> You pretty quickly shifted the goal posts there didn't you?

No my dude. You said "These numbers are always pretty BSy because the big dangers in flight are take-off and landing." That is a statement about these kind of statistics in general, not in specific to Boeings. But sure. How many accidents had Boeing during take-off or landing?

> You're also misreading your stats (that's per sector, not per million)

Negative. To quote "All accident rate (accidents per one million flights)" What is even per sector?

> Your site

Not my site? Are you arguing from good faith here?

> If you do an apples to apples comparison, vehicles would be some orders of magnitude safer than jets, trip for trip.

I will let everyone know who is considering commuting by jet twice a day for 14.6 miles.

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

#199

Post by crazytony »

nabla9 wrote: post #139
senordevnyc wrote: post #52

Earlier quoted context omitted.

While true, this was a pretty different situation in that it was 1959 (engineering standards have changed a lot in the last 65 years), and the dutch rolls were being performed intentionally for demonstration purposes.

1985 the dedliest single aircraft accident was due to dutch roll. Japan Airlines Boeing 747SR. 2013 KC-135 Stratotanker broke up in flight due to dutch roll. 2005 Airbus A310 survived with serious structural damage.

This is extremely disingenuous. A dutch roll if identified and corrected is not structurally dangerous to an aircraft but it typically signifies something wrong with the control surfaces which is a larger issue. In the majority of the cases, it's the yaw damper that's a problem (my suspicion in the 737 case).

JAL 123 crashed because hydraulic pressure on all 4 hydraulic lines and 90% of the vertical stabilizer and 100% of the rudder were lost due to an explosive decompression of the aft pressure bulkhead. Dutch rolls ensued because of the loss of lateral direction control.

The KC-135 crashed because the rudder power control unit on the rudder was faulty and the pilots failed to identify the problem. They then used alternating rudder inputs to recover which caused the structural limits of the vertical stabilizer to be exceeded its structural limits and separate (along with the rest of the tail).

The Air Transat flight (961) had the entire rudder separate from the aircraft most likely due to stress fractures. This caused the aircraft to have extremely limited lateral directional control which caused the dutch rolls.

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

#200

Post by umvi »

agurk wrote: post #123
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…

I'm not aware of a B-52 being crashed in a barrel roll, but this did make me think of the 1994 Fairchild crash[0] that was caused by a pilot who was known as dangerous due to excessive self confidence. In this case he banked too tightly at low level causing a stall into the ground. The whole crash was caught on camera[1], which is indelibly burnt into my memory. [0] - https://en.wikipedia.org/wiki/1994_Fairchild_Air_…

Thanks, my mistake, this is what I was referring to. Apparently "Bud" would brag about "rolling" B-52s (https://www.historylink.org/File/8716), but the fatal crash was actually just a low-altitude stall as you pointed out. It's now a textbook case study for systemic leadership failure.
Post reply on HN