I was towing my pop-up, it is a large Palomino about 2800 lbs. and I had not closed down the ball latch.:(
About 5 miles from home at 65 mph I hit a bump and the trailer came loose. In less time than it takes to tell the story, camper lurched left and snapped back to the right about the time that I hit the brakes hard.
When the trailer snapped to the right it broke the left chain coupling to the hitch; as it slid under bumper of the slowing truck up to the propane tank. :E
The whole incident took perhaps 6 seconds and another 25 minute to jack the truck up so I could un-wedge the camper.
There were three bone headed mistakes. First I was distracted during the hook up, second I did not lock the ball down on the hitch, third I did not insert the locking cross pin in the ball locking lever.
An accident is a collection of small mistakes.