What is the recommended action when using air brakes on steep downgrades?

The recommended action when using air brakes on steep downgrades is to alternate between brakes and engine braking. This method is effective because it helps to avoid overheating the air brakes, which can lead to brake fade and ultimately a loss of braking power. By utilizing engine braking—achieved through downshifting—you can reduce the vehicle's speed more gradually and decrease the reliance on the air brakes. This helps maintain safe control of the vehicle while navigating steep grades.

Using air brakes continuously can lead to overheating, causing the brakes to become less effective. Therefore, it is critical to use a combination of both braking methods to ensure safety and proper function. In emergencies, while the air brakes may be necessary, relying solely on them can be risky if the brakes have already been weakened from prolonged use. Additionally, completely avoiding air brakes is impractical since they are an integral part of many commercial vehicles' braking systems, especially when they are equipped with them for such scenarios.