In the event of a rupture in the secondary system of a dual air brake system, what happens?

In a dual air brake system, each circuit typically controls different sets of brakes to enhance safety and reliability. If a rupture occurs in the secondary system, the primary system remains intact and operational. This means that the rear axle brakes would still function, allowing for controlled braking. However, the steering axle brakes, which may be connected to the secondary system, would be inoperative due to the rupture. This design ensures that even with a failure in one part of the brake system, the vehicle can still maintain some level of braking capacity, specifically on the rear axle. This is a critical safety feature, as it allows the driver to have control over the vehicle despite a malfunction in the braking system.

Thus, the correct answer illustrates the balance between providing effective braking and minimizing the risks associated with brake system failures.