NTSB Preliminary Report – UPS Boeing MD-11F Crash [pdf]

Every so often they sneak in new blocks of IP addresses though so you're playing whack-a-mole with a particularly scummy opponent.

* why it failed at rotation (the first/only sudden change of direction under full throttle) rather than as soon as it was mounted onto the plane, while taxiing, as soon as they throttled up, mid-flight, or on landing. This is important because at rotation is the worst possible time for this failure: no ability to abort take-off, no ability to land safety under no or severely limited power, little time to react at all, full fuel. Knowing these failures are likely to manifest then stresses the importance of avoiding them.

* why it failed in such a way that it damaged the rest of the plane.

Not so much what was wrong with the mounting in the first place, if that's what you're asking. Presumably it was designed to withstand the forces of this moment and clearly has done so many times before.

Or are some metals impervious?

Admiral Cloudberg has a great article on AA 191 that covers exactly what happened: https://admiralcloudberg.medium.com/rain-of-fire-falling-the...

https://en.wikipedia.org/wiki/American_Airlines_Flight_191

I assume the erroneous maintenance procedures that led to the loss of AA191 were rectified a long time ago.

https://www.easa.europa.eu/en/document-library/type-certific...

That in turn reminds me of the DHL flight out of Baghdad in 2003 that was hit by a missile [0]. Absolutely amazing that they managed to keep it together and land with damage like that.

[0] https://en.wikipedia.org/wiki/2003_Baghdad_DHL_attempted_sho...

Once the reason went away, better designs took over.

They were designed to allow smaller jets to fly over the ocean further than a two engine jet was allowed (at the time). Airlines didn’t want to waste all the fuel and expense of a huge 4 engine jet, but 2 wouldn’t do. Thus: the trijet.

The rules eventually changed and two engine jets were determined to be safe enough for the routes the trijets were flying.

Using two engines that were rated safe enough used less fuel, so that’s what airlines preferred.

It was never designed to be used anywhere else as a general design. Two engines did that better.

"you know what this motorized piece of anything needs, less power"

-nobody, ever

And here's a more detailed description of that ground run incident. It also found that the failure was related to a design flaw, and mandated that aircraft be grounded for inspection and rework. https://skybrary.aero/accidents-and-incidents/b762-los-angel...

I'm not a regulator or aerospace engineer or anything like that so I can't really say which actions are or are not appropriate. But I do want to observe that these are all unique failures with unique risk profiles that can't all be painted with a single broad brush. All I was trying to do in the previous post was speculate on why a MD-11 failure could result in a grounding of the DC-10 and KC-10A as well. The first thing that came to mind is that I think those are the only remaining trijets of that general shape that are still around. Though I suppose another possibility is that they all share an identical pylon design or something like that.

It's true that you can never get to zero. There's always a chance of some catastrophic failure. The lesson of modern airline safety is that you can get extremely close to zero by carefully analyzing and learning from the failures, which is exactly why these thorough investigations are done. The lesson from UA232 was to make sure one failure can't take out all of the hydraulic systems.

In this specific instance, "the engine fell off and took out another engine, leaving the aircraft with insufficient power to climb" is definitely not in the realm of "probabilities will get you eventually." It's very much in the realm of a mechanical failure that should not happen, combined with a bad design flaw that turns that failure from a mere emergency into pretty much guaranteed death.

Cargo is held to a lower standard than passenger service, but I suspect this will still spell the end of the DC-10 and MD-11, at least in the US. Engines will fail, and for an aircraft of this size, that needs to be survivable in all phases of flight just for the safety of people on the ground.

It’s clear from the photos this wasn’t the engine failing at all, and in fact the engine kept producing a ton of thrust (probably until it ran out of fuel as it pulled it’s fuel line apart while departing the wing), and instead the thing that is supposed to be so incredibly strong that it restrains all this chaos failed.

Which is a pattern in this family of aircraft, but definitely not a common or normal thing in general eh?

Most aircraft, the engine stays with the airframe even if it turns into a giant burning pile of shrapnel and dead hopes and dreams.