When coupling your tractor to a trailer, after you raise and secure the landing gear, what do you do next?
- Connect air and electrical lines to the trailer
- Conduct a tug test to inspect the connection
- Visual inspection of the fifth wheel connection
- Supply air to the trailer and confirm the service brake is functioning ✓
Answer: D. Supply air to the trailer and confirm the service brake is functioning
After raising and securing the landing gear, supply air to the trailer and confirm the service brake is working.
Why this is the answer
The coupling steps put connecting the air and electrical lines before raising the landing gear. Once the landing gear is fully raised and its handle is stowed, the handbook says to supply air to the trailer using the trailer supply valve and establish normal air pressure. It then has you check for leakage and test brake operation by driving forward slowly. That makes supplying air and confirming the service brake the next step after securing the landing gear.
Why the other answers are wrong
- A. Connect air and electrical lines to the trailer — Connecting the air and electrical lines comes earlier in the coupling sequence, before the landing gear is raised.
- B. Conduct a tug test to inspect the connection — Checking that the coupling is secure with a tug test belongs to the earlier coupling inspection, not after the landing gear is raised.
- C. Visual inspection of the fifth wheel connection — Visually inspecting the fifth wheel jaws and connection points is done before raising the landing gear.
Remember it
Landing gear up and handle stowed: send air to the trailer, then check the brake.