Old 1st May 2016, 17:20
  #220 (permalink)  
OnePerRev
 
Join Date: Jul 2009
Location: USA
Posts: 55
Interesting how the positive Spin on accident statistics separate the new model from the predecessors, however the certification basis relies on this model being a variant, and certified to older standards.
The new standards would clearly make the main shaft a principle structural element, one that would require fatigue substantiation by testing. So the two ditchings would not have been a surprise that the finite element model incorrectly predicted the stresses. And how is the rest of the shaft? Sometimes if you simply make a part stronger where it failed, you just chase the failure somewhere else. Full scale fatigue testing based on measured loads would have prevented those issues. What else was missed in the design assumptions? The authorities should question any other PSE failure mode that was certified by Finite element.
Also, I may have misunderstood, but I recall the statement that AB increased quality inspections to one in every four, as this was an important part. How does one ask to fly on the inspected one?
-many predictions and speculations on this site, here is mine: The facts will show that this accident was preventable. Most are. Never easy to swallow that truth.
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