text: speed but of greater importance is the reduc- 
  tion in excess thrust. Since the acceleration 
  and climb performance is a function of the 
  excess thrust and power, the failure of a power- 
  plant will be most immediately appreciated in 
  in 
  this area of performance. As illustrated 
  figure 6.8, loss of one-half the maximum avail- 
  able thrust will reduce the excess thrust to less 
  the original value. Since some 
  than half 
  the excess 
  thrust is required to sustain flight, 
  which 
  the 
  airplane may be greatly reduced. The most 
  critical conditions will exist when various 
  factors combine to produce a minimum of 
  excess thrust or power when engine failure 
  occurs. Thus, critical conditions will be com- 
  mon to high gross weight and high density altitude 
  (and high 
  the case of the 
  turbine powered airplane) as each of these 
  factors will 
  reduce the excess thrust at any 
  specific flight condition. 
  
  remains to accelerate and climb 
  
  The asymmetrical power condition which 
  fails can provide 
  results when a powerplant 
  requirements. First consid- 
  critical control 
  eration is due the yawing moment produced 
  by the asymmetrical power condition. Ade- 
  quate directional control will be available 
  only when the airplane speed is greater than 
  the minimum directional control speed. Thus, 
  the pilot must insure that the flight speed never 
  falls below the minimum directional control 
  speed because the application of maximum 
  power on the functioning powerplants will 
  produce an uncontrollable yaw 
  if adequate 
  directional control is unavailable. A second 
  consideration which 
  the propeller 
  powered airplane involves the rolling moments 
  the slipstream velocity. Asym- 
  caused by 
  metrical power on the propeller airplane will 
  create a dissymmetry of the slipstream veloc- 
  ities on the wing and create rolling moments 
  which must be controlled. These slipstream 
  induced rolling moments will be greatest at 
  high power and low velocity and the pilot 
  must be sure of adequate lateral control, 
  especially for the crosswind landing. 