What should you check first when conducting a pre-trip inspection on an air brake system?

When conducting a pre-trip inspection on an air brake system, checking the air pressure gauge readings is crucial because it is essential to ensure that the air brake system has sufficient air pressure to operate effectively.

Air brakes rely on compressed air to function, and maintaining appropriate pressure levels is vital for the braking system to engage and release correctly. Insufficient air pressure can lead to brake failure or reduced braking efficiency, significantly increasing the risk of accidents. By verifying that the air pressure gauge shows adequate readings, you can confirm that the air brake system is ready and safe for operation before driving.

Other aspects, such as the condition of the steering wheel, fuel level, and tires, are important for overall vehicle safety, but they do not directly impact the functionality of the air brake system in the same way that the air pressure does. Therefore, starting with the air pressure gauge during a pre-trip inspection is the most logical and safety-oriented approach.