Under which condition is a vehicle rejected concerning air leakage at the emergency glad hand?

A vehicle is rejected concerning air leakage at the emergency glad hand when leakage is noticeable after the control valve has operated. This condition indicates that the air supply system is not functioning properly and can compromise the safety features of the vehicle. The control valve is designed to manage air pressure and airflow for the brakes, so if leakage occurs at this stage, it signifies that there is a failure in maintaining adequate pressure for the brakes to function effectively.

Leakage that becomes apparent only after the control valve operates suggests that the system is unable to hold the necessary air pressure, which could lead to brake failure or reduced braking efficiency. This is critical in ensuring that the vehicle remains safe for operation on the road, as reliable braking is essential for preventing accidents.

The other conditions described do not necessarily indicate a critical failure like the one described. For instance, a noticeable leak while idling might not reflect the actual performance of the braking system under operational conditions. Similarly, a damaged glad hand does not automatically imply that a leak exists or affects performance unless leakage is detectable after the control valve has been engaged. Lastly, leaks occurring while the vehicle is in motion do not capture the specific testing conditions related to the control valve's operation, which is crucial for evaluating the integrity of the system.