Does your home jurisdiction require air brake endorsement?

California DMV wrote:
In-Cab Air Brake Check
Note: All the Air Brakes system tests in this section are considered important and each can be considered critical parts of the in-cab air brakes tests. The items marked with an asterisk (*) in this section are required for testing purposes during the pre-trip portion of the CDL driving test. They may be performed in any order as long as they are performed correctly and effectively. If these items are not demonstrated and the parameters for each test are not verbalized correctly, it is considered an automatic failure of the pre-trip portion of the test.

Testing air leakage rate. There are two tests as follows:

Static Leakage Test
With a basically fully-charged air system (within the effective operating range for the compressor), turn off the engine, release all brakes, and let the system settle (air gauge needle stops moving). Time for one minute. The air pressure should not drop more than:

2 psi for single vehicles.
3 psi for a combination of two vehicles.
5 psi for a combination of three or more vehicles.
An air loss greater than those shown indicate a problem in the braking system and repairs are needed before operating the vehicle.

*Applied Leakage Test
With a basically fully-charged air system (within the effective operating range for the compressor), turn off the engine, release all brakes so the entire system is charged. Allow the system to settle (air gauge needle stops moving), apply firm, steady pressure to the brake pedal (brake on), and hold.

After the system settles again, time for one minute. The air pressure should not drop more than:

3 psi for single vehicles.
4 psi for a combination of two vehicles.
6 psi for a combination of three or more vehicles.
An air loss greater than those shown indicate a problem in the braking system and repairs are needed before operating the vehicle.

Note: You must be able to demonstrate this test and verbalize the allowable air loss for the examiner on this test.

If the air loss is too much, check for air leaks and fix. For testing purposes, identify if the air loss rate is too much.

*Air Compressor Governor Cut-Out Pressure Test
To perform this test, the air pressure for the vehicle must be rising when the engine is running. Run the engine at a fast idle. The air compressor governor must cut-out prior to the needle reaching 130 psi. Where the needle stops rising is the governor cut-out pressure.

For testing purposes, identify where the air governor cuts out the compressor and verbalize the maximum pressure at which this can occur.

Note: The air dryer exhausting should not be referenced as governor cut-out.

*Air Compressor Governor Cut-In Pressure Test
To perform this test, the air pressure for the vehicle cannot be rising when the engine is running. With the engine idling, slowly pump the brake pedal to reduce the air tank pressure. Watch the air pressure gauge between pumps to identify when the compressor cuts in (needle starts to rise). This should occur no lower than 85 psi.

For testing purposes, identify where the air governor cuts in the compressor and verbalize the minimum pressure at which this can occur.

*Low Air Pressure Warning Device Test
This test may be performed with engine on or off. To perform the test with the engine off, turn the electrical power on and have enough air pressure to keep the low air pressure warning device from coming on. Slowly pump the brake pedal to reduce air tank pressure. The low air pressure warning device must activate between 55 and 75 psi. For testing purposes, identify when the warning signal activates, and verbalize the legal range in which the signal must activate.

If the warning signal does not work, you could lose air pressure and not know it. This could cause sudden emergency braking in a single circuit air system. In dual systems the stopping distance will be increased. Only limited braking can be done before the spring brakes come on.

*Check that the spring brakes come on automatically. Chock the wheels. Release all parking brakes and shut the engine off. Pump the brake pedal to reduce the air tank pressure. The trailer air supply valve knob should pop out when the air pressure falls to the manufacturer's specifications (usually in a range between 20 to 45 psi). This causes the spring brakes to engage. Some trailers use an air applied emergency brake system and some trailers use spring brakes as the emergency brake system.

Check rate of air pressure buildup. With the engine at operating rpms, the pressure should build from 85 to 100 psi within 45 seconds in dual air systems. If the vehicle has larger than minimum air tanks, the buildup time can be longer and still be safe. Check the manufacturer's specifications. In single air systems (pre-1975), typical requirements are pressure buildup from 50 to 90 psi within 3 minutes with the engine at an idle speed of 600-900 rpms.

If air pressure does not build up fast enough, the pressure may drop too low during driving, requiring an emergency stop.

Test service brakes. Wait for normal air pressure, release the parking brake, move the vehicle forward slowly (about 5 mph), and apply the brakes firmly using the brake pedal. Any pulling to one side, unusual feel, or delayed stopping action should be checked.

Test parking brake. Fasten your seat belt. Set the parking brake and try to move the vehicle or allow the vehicle to slowly move forward and apply the parking brake. The parking brake should stop a rolling vehicle, or not allow any movement.

Combination Vehicle Brake Check
In addition to those already listed in Section 2, complete these checks.

Check that air flows to all trailers (double or triple trailers):

Use the tractor parking brake and/or chock the wheels to hold the vehicle.
Wait for air pressure to reach normal.
Use the trailer hand brake to provide air to the service line.
Open the emergency line shut-off valve at the rear of the last trailer (you should hear air escaping).
Close the emergency line valve.
Open the service line valve to check that service pressure goes through all the trailers, then close the valve.
If you do not hear air escaping from both lines, check that the shut-off valves on the other trailer(s) and dolly(ies) are in the OPEN position. You must have air all the way to the back for all the brakes to work.

Test tractor protection valve:

Charge the trailer air brake system. (That is, build up normal air pressure and push in the air supply knob.)
Shut off the engine.
Pump the brake pedal several times to reduce the air pressure in the tanks. The trailer air supply control should pop out or go from the normal to the emergency position when the air pressure falls into the pressure range specified by the manufacturer (usually within the range of 20 to 45 psi).
If the tractor protection valve does not work correctly, an air hose or trailer brake leak could drain all the air from the tractor. This would cause the emergency brakes to come on, with possible loss of control.

Test trailer emergency brakes:

Charge the trailer air brake system and check that the trailer rolls freely.
Stop and pull out the trailer air supply control valve or place it in the emergency position.
Pull gently on the trailer with the tractor to check that the trailer emergency brakes are on.
Test trailer service brakes:

Check for normal air pressure.
Release parking brakes.
Move the vehicle forward, slowly.
Apply the trailer brakes with the hand control (trolley valve), if so equipped.
You should feel the brakes come on. This tells you the trailer brakes are connected and working. The trailer brakes should be tested with the hand valve but controlled in normal operation with the foot pedal, which applies air to the service brakes at all wheels.