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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

#61
post #21

Earlier quoted context omitted.

It can torn off the engines from the main body structure: https://asn.flightsafety.org/asndb/333926

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.

[dead]

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

#62
post #27

Earlier quoted context omitted.

I guess it’s worse than it looks? The video was kind of a dramatic let down to be honest. I preferred the mystery.

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.

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

#63
post #27
post #20

Earlier quoted context omitted.

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

I guess it’s worse than it looks? The video was kind of a dramatic let down to be honest. I preferred the mystery.

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

#64

"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?

In plain English: unwanted tail waggle

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

#67

Earlier quoted context omitted.

> It kinda bothers me that airlines are still placing orders for new Boeing airplanes. Are they? Boeing had almost nine hundred 737 MAX orders in 2023; in 2024 they have 66: * https://en.wikipedia.org/wiki/List_of_Boeing_737_MAX_orders_... Three hundred 787 orders in 2023; 10 in 2024: * https://en.wikipedia.org/wiki/List_of_Boeing_787_orders_and_... One hundred 777s in 2023, twenty-seven in 2024: * https://en.wikiped…

I'd note Airbus is seeing the same pattern. The 737-MAX's A320neo competitor, for example: https://en.wikipedia.org/wiki/List_of_Airbus_A320neo_family_... 1,689 orders in 2023, 154 in 2024. https://en.wikipedia.org/wiki/List_of_Airbus_A220_orders_and... 141 orders in 2023, negative 12 in 2024. As a result, I presume the explanation is less "no Boeing" and more something like "orders have a reporting lag" or "2023 was…

These stats alone seem like way more interesting news, suprised I haven't seen that before. I wonder why plane orders from the two biggest manufactures have dropped so dramatically and what it means economically.

My mind immediately goes to whether airlines are quietly preparing for an expected downturn, or if airlines aren't selling to corporations because they're selling to governments and militaries. That could definitely be my own preconceptions sneaking in though.

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

#68
post #29

Earlier quoted context omitted.

I know the humorless HN is downvoting you but I gave you an upvote. Farts and fart jokes are always funny.

It’s being downvoted because it’s technically incorrect. They are describing a Dutch Oven.

Uh yes, they were being sarcastic.

Once again…the humorless HN strikes. Sheesh.

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

#69
"Dutch Roll" in context: it's one of the dynamic modes of a plane -- a bit like the "phugoid" (e.g. when your paper airplane repeatedly speeds downward, pitches up, stalls, and speeds downward again on its way to the ground).

In broad strokes, the dynamic modes can have natural frequencies -- in the same sense often used when speaking of resonance, transfer functions -- and there's a trade-off between (1) having low natural frequencies and (2) having a responsive control system.

https://en.wikipedia.org/wiki/Aircraft_dynamic_modes

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

#70
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?

Do you think your car (or bike) is safer or more dangerous than the least safe Boeing plane in service?

Per mile or per hour?
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