As discussed in Section 6.1, adequate stability is essential to safe aircraft operations. Figure 6.9 illustrates the desired initial response of the aircraft when it is disturbed from trimmed level flight. If the disturbance causes the aircraft’s angle of attack to increase, a statically stable aircraft would generate a negative pitching moment which would tend to return it to the trim condition. Likewise, if the disturbance reduced , a statically stable aircraft would generate a positive pitching moment.
