The laws of physics and aerodynamics don’t magically change when a general aviation airplane flies from the flatlands into the mountains, yet every year there are accidents in the high country where pilots tried to get more performance from an airplane than was installed. Pilots discover they can’t get airborne on the available runway or hit obstructions after takeoff; they discover downdrafts exceed the ability of their airplanes to climb and hit mountain ridges; they hit the sides of canyon walls because they can’t make a 180 in the available space; and sometimes their airplanes come to pieces around them because they decided to fly fast where there was severe turbulence.