UPS MD-11 crash

[Maxmars]

I actually asked an exec about the wording and got a dirty look...

It was hard not to laugh.

[Zaphod58]

Several other MD-11s undergoing inspection were found with serious cracks in their engine pylons. 

[Maxmars]

Several other MD-11s undergoing inspection were found with serious cracks in their engine pylons. 

....

Is that so old that the materials crystalized?

I doubt it started out looking that fragile... that can't happen all at once can it?
Is it a chemical exposure thing or just repeated stressing?

Yikes.

[Zaphod58]

Is that so old that the materials crystalized?

I doubt it started out looking that fragile... that can't happen all at once can it?
Is it a chemical exposure thing or just repeated stressing?

Yikes.

Those pylons are exposed to pretty serious vibration, especially at or near MTOW. That’s a lot of stress to put on them over and over again.

[Zaphod58]

There’s some doubt now about the picture posted above.

[Zaphod58]

The NTSB has turned the crash scene over, but is still collecting evidence. There's a lot of work to be done to the area, with gas line repairs looking at several weeks to be completed.

[Zaphod58]

Images from an airport surveillance camera released by the NTSB.

[Maxmars]

So that engine.. just 'flexed' upwards, and out of position?.... remember this is a layman asking.

[Zaphod58]

Images from the left engine pylon found after the accident. The aircraft had just over 21,000 cycles, and inspection of the failed parts would have taken place at 28,000 and 29,000 cycles.

[Zaphod58]

So that engine.. just 'flexed' upwards, and out of position?.... remember this is a layman asking.

The fore and aft fracture surfaces failed, most likely the aft first, which allowed the engine to rotate up, from the thrust pushing it.