The RTO test is performed under the worst possible conditions; i.e. with fully worn out brakes, the plane loaded to maximum takeoff weight and no use of thrust reversers. During an RTO test most of the kinetic energy of the airplane is converted to heat by the brakes, which may cause the fusible plugs of the tires to melt, causing them to deflate. Small brake fires are acceptable providing, in the first five minutes, they do not prejudice the safe and complete evacuation of the aircraft.[1]