In the scene where Dennis Quaid is rescuing the girl from the warehouse fire, he throws his helmet out the window. After falling for a while, it hits the ground. A few seconds later, you see it falling again and hit for a second time. Big Mistake.
I was watching this movie as I read what you wrote, and I had to rewind to watch that part twice, but it isn't the hat that hits twice, it's the glass that the son drops in 1999.