Figure 11-17.  Chart Supplement U.S. (formerly Airport/Facility Directory) information.  well before landing and be prepared for hydroplaning. Opt for  a suitable runway most aligned with the wind. Mechanical  braking may be ineffective, so aerodynamic braking should  be used to its fullest advantage.  Tire pressure is a factor in dynamic hydroplaning. Using  the simple formula in  Figure 11-18,  a pilot can calculate  the minimum speed, in knots, at which hydroplaning begins.  In plain language, the minimum hydroplaning speed is  determined by multiplying the square root of the main gear  tire pressure in psi by nine. For example, if the main gear tire  pressure is at 36 psi, the aircraft would begin hydroplaning  at 54 knots.  The minimum takeoff distance is of primary interest in  the operation of any aircraft because it defines the runway  requirements. The minimum takeoff distance is obtained by  taking off at some minimum safe speed that allows sufficient  margin above stall and provides satisfactory control and  initial ROC. Generally, the lift-off speed is some fixed  percentage of the stall speed or minimum control speed for  the aircraft in the takeoff configuration. As such, the lift-off is  accomplished at some particular value of lift coefficient and  AOA. Depending on the aircraft characteristics, the lift-off  speed is anywhere from 1.05 to 1.25 times the stall speed or  minimum control speed.  Landing at higher than recommended touchdown speeds  exposes the aircraft to a greater potential for hydroplaning.  And once hydroplaning starts, it can continue well below the  minimum initial hydroplaning speed.  On wet runways, directional control can be maximized  by landing into the wind. Abrupt control inputs should be  avoided. When the runway is wet, anticipate braking problems  To obtain minimum takeoff distance at the specific lift-off  speed, the forces that act on the aircraft must provide the  maximum acceleration during the takeoff roll. The various  forces acting on the aircraft may or may not be under the  control of the pilot, and various procedures may be necessary  in certain aircraft to maintain takeoff acceleration at the  highest value.  The powerplant thrust is the principal force to provide the  acceleration and, for minimum takeoff distance, the output  thrust should be at a maximum. Lift and drag are produced  as soon as the aircraft has speed, and the values of lift and  drag depend on the AOA and dynamic pressure.  Figure 11-18.  Tire pressure.  Takeoff Performance  11-14  9 x  Tire pressure (in psi)  9 x 6 = 54 knots  36 = 6  Minimum dynamic hydroplaning speed (rounded off) =  Airport name  Runway slope and direction of slope  Runway surface  Runway