What is the proper technique for descending long grades with air brakes?

The proper technique for descending long grades with air brakes involves applying the brakes just hard enough to reduce your speed to about 5 mph below the safe speed for that particular grade, and then releasing the brakes until your speed returns to the safe level. This method allows the brakes to cool and prevents overheating, which can lead to brake fade, a dangerous condition where brakes lose effectiveness due to excessive heat.

By intermittently applying and releasing the brakes in this manner, you maintain better control over your vehicle's speed without continuously applying pressure, which can cause the brakes to overheat. This technique is especially important in maintaining the longevity and efficacy of your air brake system while ensuring the safety of your descent down the gradient.

Other methods, such as applying the brakes hard and maintaining steady pressure, could lead to overheating and reduced braking power. Keeping the brakes constantly engaged is also problematic, as this does not allow them to cool and can increase the risk of brake failure. Stabbing the brakes intermittently to maintain speed might not provide the necessary consistent control and could result in loss of traction or control as well. Overall, option B provides a balanced approach that prioritizes both safety and brake maintenance.