When coupling, you should back up until:

The fifth wheel touches the trailer apron.. Section 6.4: Back until the fifth wheel just touches the trailer apron.

When coupling, you should back up until:

ANSWER BREAKDOWN
  • A. Correct. Back until the fifth wheel just touches the trailer apron.
  • B. Incorrect. "You hit the kingpin hard." is not correct. Back until the fifth wheel just touches the trailer apron.
  • C. Incorrect. "The tractor hits the nose." is not correct. Back until the fifth wheel just touches the trailer apron.
  • D. Incorrect. "You hear a noise." is not correct. Back until the fifth wheel just touches the trailer apron.