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For example , turbine fan blades are often thrown away without knowing the real state of stress and fatigue damage , because it is highly dangerous to lose a turbine blade in flight . It is only on particular occasions , when the owner of a country thinks it would be prejudicial or dangerous to allow a passage through it , that he ought to refuse permission to pass . Heavy seas made it too dangerous to launch a boat so PROVIDENCE came directly alongside INDUSTRY , locking with her rigging to take off her passengers and crew . One of the things aviation has learned is that it is very dangerous to have a pilot-in-command who is so concerned with his own status that he does not listen to the opinions of others .