What is brake fade?
Brake fade is the reduction or loss of the friction of brake pads acting against a brake disc. The brake pedal will normally still remain high, but retardation from braking has gone away. It is not a nice feeling and the normal reaction by most drivers is to push the pedal even hard, resulting in even more temperature and less friction.
Fade is a term commonly used mistakenly to describe a long brake pedal. But it is nothing to do with that. Both issues are commonly caused by excessive heat, but fade is where the friction action is reduced because the pad and disc materials, specification, design etc used are not coping with the punishment being handed to them! A thin layer of gas that sometimes forms between the pad and disc can also play role in creating fade as it acts as a barrier.
The solution to brake fade is normally a reduction in temperature at the brake pad / caliper to allow the components to get back into their ideal operating temperatures.