CDL Vehicle Combination Practice Test

When uncoupling a loaded trailer, how far should you lower the landing gear?

1. Until it is halfway to the ground

2. Until it reaches the ground

3. Only a few inches

4. When the trailer is empty

The correct answer is: Until it reaches the ground

Lowering the landing gear of a loaded trailer until it reaches the ground is essential for several reasons related to safety and stability. When the landing gear is fully extended to the ground, it ensures that the trailer is properly supported and stable, which prevents it from shifting or tipping over once it is uncoupled from the tractor. This is particularly important when the trailer is loaded, as the center of gravity will be higher, increasing the risk of instability. Leaving the landing gear only partially lowered, such as halfway or just a few inches off the ground, does not provide adequate support for the trailer. This could lead to unsteady conditions and potentially dangerous situations during the uncoupling process. Fully lowering the landing gear ensures that the trailer can stand securely on its own, allowing the driver to safely disconnect the air lines and electrical connections without concern for the trailer shifting unexpectedly. Understanding the importance of properly positioning the landing gear reinforces the need for meticulous attention to detail when handling vehicle combinations, especially with loaded trailers, to maintain safety and operational integrity.