• We know that the accident occured
  
  

fatigue(fan_blade(engine_no_1)) [1]

• Our hypothesis the pre-conditions.
  
  

forall e : fatigue(fan_blade(e)) <= 
    type(fan_blade(e), -3c-1_CFM56), 
    second_order_vibrations(e). [2]

• Find evidence to support hypothesis?

type(fan_blade(engine_no_1), -3c-1_CFM56), 
second_order_vibrations(engine_no_1).

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