text: limit 
  trollability while the aft c.g. limit 
  the minimum permissible stability. 
  LONGITUDINAL DYNAMIC STABILITY. 
  All previous considerations of longitudinal 
  stability have been concerned with the initial 
  tendency of the airplane to return to equilib- 
  rium when subjected to a disturbance. The 
  considerations of longitudinal dynamic sta- 
  bility ate concerned with time history response 
  of the airplane to these disturbances, i.e., the 
  variation of displacement amplitude with 
  time 
  following a disturbance. From previous deli- 
  nition, dynamic stability will exist when the 
  amplitude of motion decreases with 
  time and 
  dynamic instability will exist if the amplitude 
  increases with time. 
  
  is set by the minimum permissible con- 
  is set by 