To uncouple ground air lines from equipment, what should you do first if equipped?

• A. Operate the bleed valve on the ground air to release the pressure
• B. Open the angle cock on the equipment
• C. Disconnect the ground air hose
• D. Inspect the coupling for signs of wear

Answer: (A)

Relieve the pressure first by operating the bleed valve on the ground air line. Ground air is under significant pressure, and disconnecting while it’s still charged can cause a sudden air release that could injure you or affect the braking system. Bleeding the line brings it to a safe pressure, after which you can proceed with isolating and disconnecting. The other steps—such as closing the angle cock, then disconnecting, and finally inspecting the coupling—come after depressurizing.