In the Novel catch-22 by the American writer Joseph Heller,catch-22 stipulates that only if a soldier is mentally abnormal and he or she applies to stop flying, he or she can be allowed to stop flying
According to common sense, if a soldier is aware of the danger of flying and applies to stop flying, it shows that he is clear-headed and his mind cannot be abnormal
If a person is mentally abnormal, he will be allowed to stop flying.