You’ve parked your tractor and are about to uncouple from the trailer. The trailer is going to be sitting by itself until another tractor picks it up. What keeps the trailer from tipping forward or sinking into the pavement? The landing gear — the retractable support legs that hold the trailer level and stable when it’s not connected to a tractor.
Landing gear is the support assembly on the front of a semitrailer consisting of two legs with retractable telescoping tubes and a hand crank or hydraulic system. When extended, the landing gear supports the trailer’s front end when it’s uncoupled from the tractor. The legs have feet or pads that distribute weight and prevent the trailer from sinking into soft ground. Proper landing gear operation is essential for safe uncoupling and coupling procedures.
Why Landing Gear Matters for Your Driving Test
The uncoupling procedure is a major portion of the CDL skills test, and proper landing gear operation is critical. You must extend the landing gear to support the trailer before uncoupling, ensure it’s fully engaged, and verify the trailer is stable before driving away. Leaving the trailer unsupported or failing to fully extend the landing gear is an automatic test failure.
What You’ll See on the Road
The landing gear is mounted on the front of the semitrailer, just behind the kingpin. During uncoupling, you’ll extend the legs to support the trailer weight. During coupling, you’ll retract them so the trailer can be pulled away from the tractor.
“Time to uncouple,” you think during the skills test. “First, I’ll lower the landing gear until it contacts the ground, then keep lowering until the fifth wheel is clear of the kingpin. Need to make sure the trailer is stable before pulling the tractor away.”
Common Pitfall & Pro Tip
⚠️ Pitfall: Not extending the landing gear far enough before uncoupling. Many drivers lower it until it just touches the ground, then uncouple. But the trailer’s front end weight will compress the landing gear further, potentially causing it to collapse or sink into the ground.
💡 Pro Tip: Extend the landing gear until it takes the full weight of the trailer front end. You should see the fifth wheel rise slightly off the kingpin, indicating the landing gear is bearing the full load. Only then is it safe to disconnect and pull the tractor away.
Memory Aid for Landing Gear
Think “Before Leaving, Lower Gearing.”
Before uncoupling, Lower the Landing Gear fully. This reminds you that landing gear extension is the first critical step before you can disconnect and leave the trailer.
Driving Test Connection
Landing gear operation is tested during the uncoupling procedure of the CDL skills test. You’ll demonstrate proper extension, verify the trailer is stable, and ensure it’s fully retracted during coupling. The written exam includes questions about uncoupling procedures and trailer support.
Related Driving Concepts
Landing gear is central to uncoupling and coupling procedures. It’s essential for semitrailer operation when parked without a tractor. Understanding landing gear relates to proper combination vehicle handling and ensuring trailer stability during storage or loading.
Quick Reference
✓ Key Rule: Extend landing gear fully before uncoupling; retract fully before coupling.
✓ Exam Priority: Critical Check — automatic failure if trailer is left unsupported.
✓ Driver Actions:
- Inspect landing gear for damage, cracks, or wear during pre-trip inspection.
- Before uncoupling, extend landing gear until it supports trailer weight.
- Verify landing gear legs are fully engaged and locked.
- Ensure trailer is stable before disconnecting tractor.
- During coupling, retract landing gear fully before pulling trailer away.
- Check landing gear feet for damage or sinking on soft ground.
Landing gear is what keeps your trailer standing tall when you’re not there. Extend it fully, check for stability, and your trailer will be safe until you return.