Report on accident involving tanker on the E6 road in Mosjøen 19 January 2017

The heavy goods vehicle was on its way from Jaren in Oppland county to Tromsø Airport carrying 29,200 litres of de-icing fluid. As it was going through a right curve approximately 10 kilometres north of Mosjøen, the vehicle skidded to the left before it rolled over and came to rest outside the roadway. The bolts fastening the semi-trailer’s coupling mechanism broke in the process, and both the tractor unit and the trailer suffered extensive damage.

The investigation has found that the heavy goods vehicle was travelling at a speed around the critical curve speed for the curve in question. A combination of variable road surface conditions at the site and different tyre properties on the tractor unit and the semi-trailer may have contributed to the trailer skidding.

Extensive technical investigations have been carried out of the fracture surfaces on the bolts that secured the coupling mechanism to the semi-trailer. The investigation shows that the bolts snapped as a result of overload. The AIBN believes that the fastening bolts broke as a result of the heavy goods vehicle rolling over, and were thus was not a contributing factor to the semi-trailer losing its grip on the road and skidding to the left.

No safety recommendations are proposed as a result of this investigation.