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Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by kcplate on Thursday June 13, 2024 @08:18AM (#40668730)
I guess it’s worse than it looks? The video was kind of a dramatic let down to be honest. I preferred the mystery.
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by JWlrCk9PkipFTDq on Thursday June 13, 2024 @08:29AM (#40668831)
It looks a bit more intense in real footage.

https://www.youtube.com/watch?v=2tgfkGiHhxs

Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by Ringz on Thursday June 13, 2024 @12:03PM (#40671336)
This should be the top comment.
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by kcplate on Thursday June 13, 2024 @09:09AM (#40669195)
Agreed.
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by grapescheesee on Thursday June 13, 2024 @07:58PM (#40676199)
Yeah, this has some elevation reference, and much more dramatic shifting.
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by ceejayoz on Thursday June 13, 2024 @08:28AM (#40668823)
A real-world video looks a lot scarier.

Linked downthread: https://www.youtube.com/watch?v=2tgfkGiHhxs

Especially if close to the ground.

Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by albert_e on Thursday June 13, 2024 @08:34AM (#40668885)
this video posted elsewhere here seems dramatic enough

https://www.youtube.com/watch?v=2tgfkGiHhxs

Imagine you are in the cockpit at the top of the plane and your view/perspective - for a layman like me this would seem and feel like the flight is completely out of control. Even the passengers are bound to experience dramatic movements similar to severe turbulence I guess.

Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by seanhunter on Thursday June 13, 2024 @08:48AM (#40669003)
Idk. The idea of trying to control the aircraft which is doing this while being responsible for >100 lives seems pretty terrifying to me.
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by FrustratedMonky on Thursday June 13, 2024 @08:22AM (#40668762)
Yeah, could this be caused by turbulence? Winds?

Looking at the video, now i'm not sure I haven't been through some dutch rolls also.

Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by SonicScrub on Thursday June 13, 2024 @08:47AM (#40668992)
Dutch Roll is a coupling of yawing and rolling dynamic modes, and is a product of the aircraft's aerodynamics. If the aircraft is disturbed off a steady-state path either by control input, changing winds, or turbulence, then it should return back to it's steady-state path with oscillations that quickly dampen. Dutch Roll is a phenomenon where these oscillations grow rather than dampen as a result of out-of-phase yaw and roll modes.

So Dutch Roll can be triggered by turbulence/wind, but the Dutch Roll itself is the result of something going wrong in reaction to that stimulus. This is different than the aircraft just being batted around by turbulence.

Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by account42 on Thursday June 13, 2024 @10:27AM (#40670125)
> This is different than the aircraft just being batted around by turbulence.

Does it actually look different or is it just a different cause for similar movement patterns?

Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by SonicScrub on Thursday June 13, 2024 @01:39PM (#40672387)
Just being batted around by turbulence looks different if you know what you're looking for (although what to look for might be only obvious when looking at accelerometer data). Again, Dutch Roll is a very specific phenomenon as a result of coupling between the roll and yaw dynamic modes. The risk of Dutch Roll is that these oscillations can grow even without further stimulus rather than just dampen out.
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by belter on Thursday June 13, 2024 @08:27AM (#40668807)
The FAA reported: "AIRCRAFT EXPERIENCED A DUTCH ROLL, REGAINED CONTROL AND POST FLIGHT INSPECTION REVEALED DAMAGE TO THE STANDBY PCU, OAKLAND, CA." and stated the aircraft sustained substantial damage, the occurrence was rated an accident.
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by HPsquared on Thursday June 13, 2024 @08:40AM (#40668944)
Standby PCU sounds like a control system. Was that a cause or effect of the event?
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by banannaise on Thursday June 13, 2024 @09:00AM (#40669106)
The PCU in this context is the part that moves the rudder. PCU issues were common on the 737 in the 90s[0] although that's... probably?... not relevant here.

[0] https://en.wikipedia.org/wiki/Boeing_737_rudder_issues

Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by HPsquared on Thursday June 13, 2024 @09:13AM (#40669250)
Exactly, rudder control issues could trigger or exacerbate Dutch roll. Loss of yaw damper control, in other words (yaw damper actuates the rudder).
Re:Southwest Airlines Boeing 737-8 Max Experienced Dutch Roll by DiggyJohnson on Thursday June 13, 2024 @10:47AM (#40670380)
For what its worth, that's very unlikely in the last decade or so. More likely to be moderate turbulence, which would be nearly indistinguishable in a non-severe event.