51. When you are uncoupling a loaded trailer, lower the landing gear until it:
Detailed Explanation
The correct answer is "c. Makes firm contact with the ground.". This question tests cargo securement, weight distribution, and preventing a load from changing vehicle control. For a differently worded version of this question, identify the hazard first and then choose the answer that preserves control, visibility, or legal compliance.
Correct Answer: c. Makes firm contact with the ground.
Why This Matters on the CDL Test
Use this question to review load securement and vehicle balance. On the real CDL exam, cargo questions often test whether you understand how weight, center of gravity, and securement affect control before the vehicle ever moves.
How to Remember It
Say the rule in your own words, then explain why the wrong answers are unsafe or incomplete. That habit makes similar Combination Vehicles questions easier when the exam changes the wording.
Answer Review
Choose "c. Makes firm contact with the ground." because this answer matches the safe CDL action for coupling and trailer support inspection. On the knowledge test, the safest answer is usually the one that protects space, control, visibility, legal compliance, or inspection accuracy before the vehicle is put at risk.
Why the other answers are weaker
- a. Reaches the ground."a. Reaches the ground." does not best answer this coupling and trailer support inspection question. When you see a similar option on the CDL permit test, compare it against the exact safety rule and choose the answer that prevents the most immediate risk.
- b. Makes contact with the ground and leaves the trailer off the fifth wheel."b. Makes contact with the ground and leaves the trailer off the fifth wheel." does not best answer this coupling and trailer support inspection question. When you see a similar option on the CDL permit test, compare it against the exact safety rule and choose the answer that prevents the most immediate risk.
Test-Day Checklist
- Read the question once for the topic, then read it again for the exact CDL action being tested in Combination Vehicles.
- Eliminate answers that sound convenient but skip an inspection, warning sign, or safety step.
- Say the correct rule out loud before moving on so you can recognize it when the exam changes the wording.
Ready to practice for real?
Take our free, full-length Combination Vehicles practice test. Simulates the actual DMV exam with timed questions.
Start Practice TestRelated Questions
34. Where should the tractor be when you inspect landing gear after uncoupling the trailer?
When uncoupling a trailer, landing gear should be:
2. You should not back a tractor under a trailer until the whole air system is:
46. You have pushed the trailer air supply valve. You should not back a tractor under a trailer until the whole air system is:
48. After you have coupled the trailer you should have to raise the landing gear by using:
Keep Studying Combination Vehicles
Question pages help you review one rule at a time. To build test-day speed, move back into the full Combination Vehicles practice test and answer a mixed set without looking at the explanation first.
State CDL Practice Paths
After you understand this answer, use a state practice path to connect the federal CDL rule with the DMV test pages drivers search for most.