text: Thus, 10 percent excess airspeed would increase 
  the takeoff distance 21 percent. 
  In most criti- 
  cal takeoff conditions, such an increase in 
  takeoff distance would be prohibitive and the 
  pilot must adhere to the recommended takeoff 
  speeds. 
  
  The effect of prcs~wc altitude and ambient 
  rcmpcraturc is to define primarily 
  the density 
  altitude and its effect on takeoff performance. 
  While subsequent corrections are appropriate 
  for the effect of temperature on certain items 
  of powerplant performance, density altitude 
  defines certain effects on takeoff performance. 
  An increase in density altitude can produce a 
  two-fold effect on takeoff performance: (I) 
  in- 
  creased takeoff velocity and (2) decreased 
  thrust and reduced net accelerating force. 
  If 
  a given weight and configuration of airplane is 
  taken to altitude above standard sea level, the 
  airplane will still 
  require the same dynamic 
  pressure to become airborne at the takeoff lift 
  coefficient. Thus, the airplane at altitude will 
  take 05 at the same equivalent airspeed (EAS) 
  as at sea level, but because of the reduced 
  density, 
  be 
  greater. From basic aerodynamics, the rela- 
  tionship between true airspeed and equivalent 
  airspeed is as follows: 