What is the correct sequence for uncoupling a trailer?

What is the correct sequence for uncoupling a trailer?

• A. Unlock the trailer coupler, then stop
• B. Lower landing gear first
• C. Set parking brakes after chocking
• D. Stop, set parking brakes, chock wheels, unlock the trailer coupler, and lower landing gear if necessary.

Answer: (D)

The sequence is about keeping the rig stable and safe while disconnecting. Start by bringing the vehicle to a complete stop and applying the parking brakes so nothing can move. Then place wheel chocks around the trailer wheels to lock in place any potential movement during uncoupling. After the rig is secured, unlock the trailer coupler to release the connection. Lower the landing gear to support the trailer’s weight only if needed; this stabilizes the trailer once it’s separated from the tractor. This order matters because moving before the brakes are set or before the trailer is chocked can lead to unintended movement, creating a dangerous situation. Lowering the landing gear too early could allow the trailer to drop or shift before it’s fully supported, and unlocking the coupler without preventing movement risks the trailer rolling away. The described sequence maximizes stability and safety during uncoupling.

The sequence is about keeping the rig stable and safe while disconnecting. Start by bringing the vehicle to a complete stop and applying the parking brakes so nothing can move. Then place wheel chocks around the trailer wheels to lock in place any potential movement during uncoupling. After the rig is secured, unlock the trailer coupler to release the connection. Lower the landing gear to support the trailer’s weight only if needed; this stabilizes the trailer once it’s separated from the tractor.

This order matters because moving before the brakes are set or before the trailer is chocked can lead to unintended movement, creating a dangerous situation. Lowering the landing gear too early could allow the trailer to drop or shift before it’s fully supported, and unlocking the coupler without preventing movement risks the trailer rolling away. The described sequence maximizes stability and safety during uncoupling.