SEATTLE - A pilot driver guiding an oversize load that triggered an Interstate 5 bridge collapse north of Seattle told investigators that the clearance pole mounted on her car never hit the structure.
But in documents released by federal investigators Wednesday, at least one witness reported seeing the pole hit the Skagit River bridge, indicating there may not have been proper clearance for the oversize load.
The National Transportation Safety Board is investigating the May 23, 2013, bridge collapse. A section of the span fell into the water after a truck carrying an oversize load hit the bridge about 60 miles north of Seattle.
Brief security camera video is the only recorded visual of the collapse, and the spectacular scene seem to be as mucha of a surprise to the truck’s driver as it did to anybody else.
"...It was just a horrendous boom and things were -- it was violent in the cab," Canadian driver William Scott told investigators.
He was in the right lane, where the clearance was lowest, because the bridge's beams formed an arch and were highest in the center.
"But I had no indication that we couldn't be where we were. The pole went through,” he said.
The 16-foot pole was on a pilot car driven by Tammy Detray. Both vehicles were in the right lane.
"I knew she was out there with enough time if she'd have said stop, I could have stopped the truck, right. I know the bridge was good for 16 feet."
But it wasn't. The height of the load was measured at just under 15 feet 11 inches. Two inches higher than what the driver said it was and an inch over the permit height.
As the truck was pushed farther to the right, it came into contact with the curved arch of the bridge, which was just 15 and one half feet at the right edge of the lane. Five inches lower than the load.
And the pole on the pilot car was said to be set at 16 feet two inches. But while the pole was mounted on the right side of the front bumper, it tilted to the centerline of the truck and away from the curving bridge beams.
Scott talked about driving further into the center, but he said he was crowded to the right by another truck, a semi seen in NTSB photos.
Other points revealed in the documents:
- The truck driver says he was supposed to have four pilot cars meet him at Sumas. One didn't show up. A second left to look for that car. A third went a few miles down the road, then turned back to Sumas, leaving one pilot car.
- The driver says he crossed the bridge five or six times since 2005. All were oversized loads. He said he never had a problem.
- The driver tested negative for drugs and alcohol.
- He said it was very windy that day.
Documents show that the pilot driver was on the phone at the time of the accident, on a hands-free device.
The documents released Wednesday are not the NTSB's final report and they do not give the probable cause. That is expected this summer.
Here is a look at what Wednesday's documents reveal. Read full report