Wrathall Mark wrote:

Mark Wrathall wrote>

Paul, do you want the A300 crash discusions moved off your forum? Here is
the latest NTSB release.
http://www.ntsb.gov/Pressrel/2001/011120.htm

If there is an age problem with composites I think we ought to know
about it. Many of us are building and flying composite airplanes.
Some even with carbon fiber structural parts. This has implications for the 
aviation industry far beyond Airbus.

The fact that these metal attachment lugs and bolts are un-deformed is highly
suspicious to me. That means the  carbon was much weaker, at this time, than 
the metal lugs and bolts. Engineers strive to make all parts equally strong. 

The fragmented carbon in the left side of this picture suggest this is 
the origin of failure. The carbon appears to have first failed in shear 
between the layers. My guess is the next point shown in the picture just 
ahead of or behind this failed next in simple tension as the load on it 
was suddenly doubled. 

That allowed the fin to move lateral towards the photographer. 
The hard points on the other side of the fin then failed due to lateral 
bending of the fin. This was a simple brittle fracture caused by bending
in the carbon lugs from the looks of the photos. Again the metal lugs 
are much stronger than the carbon as they show no permanent deformation. 

Paul Lamar
 
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