Nigel said
Lightning strikes, etc are not the fault of the blade
Which is true - a blade is not a sentient being so couldn't really ever be considered to be at fault
However, the manufacturer / overhauler ... now that is a different matter. If a blade has a lightning strike, is sent back for overhaul, then subsequently fails killing lots of people, and it transpires that a manufacturing defect resulted in the lightning strike seriously weakening the spar, and that defect was not noticed at manufacture nor during overhaul, nor was the damaged spar, then someone is at fault.
HC