text: The failure of an engine during the optimum 
  cruise of a multiengine turbojet airplane will 
  cause a noticeable loss of range. Since the 
  optimum cruise of the turbojet is generally a 
  thrust-limited cruise, the loss of part of the 
  total 
  the airplane must 
  descend to a lower altitude. For example, if a 
  twin-engine jet begins an optimum cruise at 
  35,000 ft. (e=O.31) and one powerplant fails, 
  the airplane must descend to a lower altitude 
  so that the operative engine can provide the 
  cruise thrust. The resulting altitude would be 
  approximately 16,030 ft. (~=0.61). 
  Thus, the 
  airplane will experience a loss of the range 
  remaining at the point of engine failure and 
  loss could be accounted for by the reduced 
  velocity (TM) and the increase in specific fuel 
  consumption (c~) from the higher ambient air 
  temperature. 
  In the case of the example air- 
  plane, engine failure would cause a 30 to 40 
  percent loss of range from the point of engine 
  failure. Of course, the jettisoning of expend- 
  able weight items would allow higher altitude 
  and would increase the specific range. 