What condition defines a major defect related to air loss rate during an inspection?

The condition that signifies a major defect related to air loss rate during an inspection is when the pressure drops 3 psi or more for 1 minute. This specific measurement indicates a significant air leak in the vehicle's air brake system or tires, potentially impacting performance and safety.

A pressure drop of this magnitude suggests that there is an ongoing issue that could lead to failure of the air brake system, which is critical for the safe operation of heavy vehicles. This measurement is used as a standard criterion during inspections to ensure that the vehicle is in proper working condition. Identifying such a defect is essential for preventing accidents and ensuring that vehicles are compliant with safety regulations.

In contrast, a drop of less than 2 psi typically indicates a minor issue that may not compromise safety immediately. Similarly, if the pressure remains stable, it suggests that the system is functioning correctly without any leaks. Thus, the emphasis on a 3 psi drop over 1 minute as the threshold for a major defect highlights the need to address any significant air loss to maintain vehicle safety.