Craig Fink wrote:

One of the other interesting failure was in some of the seat
structure, "broom-straw" fractures 3.1-16. Aluminum is a good conductor of
heat, but it also has a huge thermal expansion coefficient. I haven't seen
a "broom-straw" fracture before. Seems that Aluminum 7075 is a laminate
material.


That's one of the_really_ strange photos in the report, isn't it?
You would think that the aluminum frames of the chair supports would
have been a lot more homogeneous than shown; particularly in regards to
their internal microscopic structure.

Pat