I'm surprised at how low a % safety buffer that is. 150% of what the engineers believe the wing will ever experience? I'd like to see 200% or more....and it's worth a little more weight and fuel consumption to have it.
Incidentally, I'm suprised they tested without the control surfaces bolted onto the wing as I can imagine that the location points of the control surfaces would have experienced some point loading thereby increasing the chance of a catastrophic failure.
Once CF goes beyond its stress limit and cracks it's done. As in, the whole piece is done. There's no repairing it. Very different than most metals. Many years ago I saw equivalent stress testing down at the Boeing plant in Seattle with metal wings and it was a different approach - stress the wing beyond it's limits and see what results. Many times the wing would spring back to normal after looking like a pretzel. In contrast, CF would be reduced to a pile of broken pieces on the floor...but I'm guessing that's not a test Boeing wants to run, and certainly would not want the media to have access to.
My last company made extremely precise sensors for the singular purpose of detecting flaws (including stress induced cracks) in CF. The US Air Force bought our sensing equipment, as did Boeing and Airbus, as our tech vastly surpassed any other sensing technology. When you look at CF that has been stressed to the point of cracking, it looks like a piece of balsa wood that's been run over by a truck. That's definitely not a wing you want to have holding up you and your family at 30,000 feet.
CF is being used in large commercial planes for one reason: the plane weighs less so you can reduce fuel consumption. Once again, it's all just a matter of an operating cost reduction for the airlines, and it has nothing to do with what's right or what's a safer way to fly.
