text: If the controls are fully powered and actu- 
  ated by an irreversible mechanism, the sur- 
  faces are not free to float and there is no differ- 
  ace between the stick-fixed and stick-free 
  static stability. 
  The control 
  
  Since each value of lift coefhcient corresponds 
  to a particular value of dynamic pressure re- 
  quired to support an airplane in level flight, 
  uim airspeed can be correlated with elevator 
  deflection as in the third graph of figure 4.13. 
  If the c.g. location is ahead of the stick-fixed 
  neutral point and control position is directly 
  related to surface deflection, the airplane will 
  In 
  give evidence of stick podion mbility. 
  other words, 
  require the 
  the airplane will 
  stick to be moved aft to increase the angle 
  of attack and trim at a lower airspeed and to 
  to decrease the angle of 
  be moved forward 
  attack and trim at a higher airspeed. To be 
  sure, it is desirable to have an airplane demon- 
  If 
  strate this feature. 
  the airplane were to 
  the airplane 
  instability, 
  have stick position 
  would require the stick to be moved aft to trim 
  at a higher airspeed or to be moved forward to 
  trim at a lower airspeed. 