text: the visual t;eference field is 
  
  In 
  order for an airplane to achieve ‘equilibrium at 
  constant altitude, lift must be equal to weight 
  and thrust must be equal to drag. Steady, 
  level flight 
  the 
  vertical and horizontal directions. For the 
  case of climbing or descending flight condi- 
  tions, a component of weight is inclined along 
  is 
  the flight path direction and equilibrium 
  achieved when thrust is not equal to the drag. 
  When the airplane is in a steady climb or 
  descent, the rate of climb is related by the 
  following expression: 
  
  RATE OF CLIMB AND .DESCENT. 
  
  For the conditions of steady flight with 
  a given airplane, each angle of attack corre- 
  sponds to a specific airspeed. Each angle of 
  attack produces a specific value of CL and each 
  value of C, requires a specific value of equiva- 
  
  350 