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SAFTEY FIRST / Post date:
1 March 2015

Because there have been two recent near-miss incidents within the BP system, this article focuses on the importance of proper coupling and pre-inspection procedures for tractor trailers.

Untitled-52Two trailers uncoupled from the tractors pulling them after travelling for approximately one-half mile. The landing gear from the trailer involved in the first accident actually became wedged between the tractor frame and the tandem axle and prevented it from tipping over.

In the second incident, the driver stated he felt the trailer coming loose and he was able to stop before the trailer became completely disengaged. Luckily, the trailer stayed upright because the nose of the trailer was still resting on the frame of the tractor when the driver stopped.

Both of these accidents involved experienced drivers; however, neither driver followed proper coupling or pre-trip inspection procedures. Both drivers stated that it “sounded” like the fifth wheel locked when they backed under the trailer, but they never did a tug test or a visual check.

Pre-trip inspections and coupling of trailers is a basic skill required of any professional driver. A driver should NEVER cut corners and assume the trailer is properly coupled because it “sounded” like it coupled.

The following is a list of generally accepted coupling procedures that are found in many state CDL training manuals. As there are differences in equipment, these should be used only as general guidelines. It is very important to always learn the details on the proper coupling procedures for the equipment you are using.

Inspect Fifth Wheel: Check for damage/missing parts, jaws open, fifth wheel greased and in the proper position.

Inspect the area and chock wheels: Make sure the area is clear and the trailer wheels are chocked.

Position Tractor: Put tractor directly in front of the trailer and never back under the trailer at an angle.

Back slowly: Back up only until the fifth wheel touches the trailer, do not hit the trailer.

Secure tractor: Put on the parking brake and place transmission in neutral.

Check trailer height: Trailer should be low enough that it’s raised slightly when the tractor is backed under it. (If the trailer is too low the tractor may damage it, if the trailer is too high, it may not couple correctly) Check that the kingpin and fifth wheel are aligned.

Connect air lines to trailer: Connect emergency and service air lines to trailer and make sure they are safely supported so that they won’t be crushed or caught while the tractor is backing under the trailer.

Supply air to trailer: When you are sure the air pressure is normal, lock the trailer brakes.

Back under trailer: Back slowly and avoid hitting the kingpin too hard. Stop when the kingpin is locked into the fifth wheel.

Check coupling for security: Raise the trailer landing gear off ground. Pull tractor gently forward while the trailer brakes are locked to check that the trailer is locked onto the tractor.

Secure vehicle: Put transmission in neutral and parking brakes on, shut off engine and take keys.

Inspect coupling: Make sure there is no space between the upper and lower fifth wheel. Check that the fifth wheel jaws are around the kingpin, that the locking lever is in the lock position, and that the safety latch is over the locking lever.

Connect the electrical cord: Plug the electrical cord into the trailer and check air and electrical lines for damage. Be sure lines will not hit any moving parts.

Raise the landing gear all the way up: Never drive with the landing gear only part way up. Secure the crank handle.

Remove wheel chocks: Remove and store wheel chocks. Please beware of hazards related to not following proper coupling procedures. Failure to follow proper coupling procedures can lead to trailer rollaway situations that may result in costly equipment damage, injuries or fatalities.


Always remember, Safety First!