In a Class 1A air brake test using the LEAKAGE method, what is the first action required?

In a Class 1A air brake test utilizing the LEAKAGE method, the first required action is to charge the system to within 15 psi of the regulating valve. This step is essential because it ensures that the air brake system is ready for a proper assessment of its functionality. By adequately charging the system, you create the right conditions to measure for any potential leaks accurately.

If the system is not sufficiently charged, you could receive erroneous readings on leakage, which could lead to a misunderstanding of the system's condition. Charging to the specified level ensures that there is enough pressure for accurate brake performance evaluation while also allowing for proper functioning of the brake system components during the test. This sets the stage for any subsequent actions required in the LEAKAGE method testing process.