Q
47. You are coupling a tractor to a semi-trailer. You have connected the airlines. Before backing under the trailer you should:
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Aa. Supply air to the trailer system, then pull out the air supply knob.
Bb. Pull ahead to test the glad hands connections.
Cc. Make sure that the trailer brakes are off.
Detailed Explanation
The correct answer is "a. Supply air to the trailer system, then pull out the air supply knob.". This is based on federal CDL regulations and safety standards.
Correct Answer: a. Supply air to the trailer system, then pull out the air supply knob.
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