Investigators of a fatal tractor-trailer separation incident in New York State have learned that a bent component affected the secondary locking mechanism of the tractor's fifth wheel, preventing it from locking correctly.

On May 29, seven occupants of a passenger van that collided with the trailer after the separation were killed. One occupant of the van suffered only minor injuries.

The New York State Department of Transportation and the Cortland County Sheriff's Department say detailed inspections of the fifth wheel found the primary lock mechanism appeared to function properly, and it was determined that the vehicles were correctly coupled before the incident. When the trailer was coupled to the tractor, the fifth wheel jaws appeared to have properly locked around the kingpin. The release handle would move into position so that it too appeared to be operating normally. However, when a pull test was conducted, the trailer disconnected.

When investigators dissected and inspected the fifth wheel, they found a bent component that affected the secondary locking mechanism of the fifth wheel preventing it from locking correctly. (The police report does not name the component.) The cause of the bent component is unknown, but it was not believed to have resulted from the accident.

The tractor-trailer separated 13.6 miles from where it was coupled, causing the trailer to cross into a lane of oncoming traffic where it collided with the passenger van.

No criminal charges were filed as a direct result of the separation incident, but a compliance review conducted on the operator, Duane Newton, found multiple administrative violations. They include failing to maintain driver qualification files, failing to maintain inquires into driver’s driving record, failing to require drivers to complete a record of duty status, failing to keep minimum records of inspection and vehicle maintenance, failing to require drivers to prepare Driver Vehicle inspection reports, and using a commercial motor vehicle not periodically inspected. The administrative violations found do not appear to have caused the accident, say the investigators.

The tractor-trailer was driven by Ryan Dorward, 26, of Manlius, N.Y. Duane Newton, 44, was a passenger in the truck; neither was injured in the crash.