text: The coefficient of braking friction can reach 
  peak values of 0.8 but ordinarily values near 
  0.5 are typical for the dry hard surface runway. 
  Of course, a slick, icy runway can reduce the 
  maximum braking friction coefficient to values 
  as low as 0.2 or 0.1: 
  If the entire weight of 
  the airplane were the normal force on the brak- 
  ing surfaces, a coefficient of braking friction of 
  0.5 would produce a deceleration of %g, 16.1 ft. 
  per sec.a Most airplanes in ground effect 
  rarely produce lift-drag ratios lower than 3 or 
  4. 
  If the lift of the airplane were equal to the 
  weight, an L/D = 4 would produce a decelera- 
  tion of xg, 8 ft. per sec.*By this comparison 
  it should be apparent that 
  friction braking 
  offers the possibility of greater deceleration 
  than airplane aerodynamic braking. To this 
  end, the majority of airplanes operating from 