The plane which is defined by the head-to-foot and anterior-to-posterior directions in the human body. A stack of images acquired in the sagittal plane separates images by their left-to-right locations. The mid-line sagittal plane bisects the left and right half of the human body.
Under heavy braking, the rear tires lock up and the axle begins to bounce; the amplitude of the bounce becomes so severe that the tires finally develop enough traction (when slamming hard against the pavement) to rip the whole axle assembly free of the vehicle.
Eventually, if the leak is not repaired, the truck can lose braking power in that portion of the system, reducing the ability to stop in the same distance. With air brakes, the opposite happens. If there is a leak in the air brake lines, the air pressure decreases, which actually activates the brakes at the wheels and brings the vehicle to a safe stop.