NZTA
Structural cracks on a cross-member in the skid plate / king pin assembly of a refrigerated trailer.
The NZ Transport Agency has written to the owners of 1800 heavy vehicles requiring their towing connections to be assessed by a specialist certifier and new certifications issued.
The action follows safety alerts issued by the agency after three incidents of cracking in truck trailers or trailer connections.
But the freight industry appears to be downplaying the significance of the problem, possibly because many trucks are owned by drivers who work for the large firms.
NZTA
Crack identified on trailer’s drawbar after about two years in service.
One of the country’s biggest freight firms, Freightways, said it had no issues and wouldn’t comment further.
NZ Trucking Association chief executive Dave Boyce said said he’d had little feedback from members, and so did Road Transport Association chief executive Dennis Robertson, who said cost might become an issue.
The safety alert was the first step in identifying and re-certifying all potentially affected vehicles that have had towing connections certified by Nelson-based Peter Wastney Engineering over the past 10 years.
Independent engineering reviews had established that drawbeams and drawbars identified with cracks and other issues were not adequately designed for the loads to which they had been certified.
The safety alert requires all operators with drawbeams, towbars, or drawbars certified by Peter Wastney Engineering to urgently have them cleaned and inspected for signs of cracks or other failures.
If any cracks or failures are found, operators have been instructed to replace affected parts before using it as a combination vehicle.
A separate safety alert has been issued providing advice on separate issues identified with skid plate couplings for refrigerated trucks.
The safety alert is focusing on monocoque refrigerator semi-trailers primarily but recommends checking of all semi-trailer skid plates as a precaution.
The safety alert follows an incident where the driver of an articulated truck and trailer combination noticed the trailer was not sitting as expected and was able to bring the vehicle to a stop without disconnection.
The safety alert applies to all refrigerated semi-trailers – not just MaxiTrans.
“While the skid plate that failed was a MaxiTrans trailer, the design of other makes of refrigerated semi-trailers is similar, so the alert applies to all refrigerated semi-trailers. We estimate approximately 1000 vehicles could be affected.
In one incident in Nelson-Marlborough in August, a trailer completely disconnected from the truck towing it.
“The trailer failed, it disconnected from the vehicle,” NZ Transport Agency operational standards manager Craig Basher earlier told Radio New Zealand.
In a second incident in December, the driver of a refrigerated semi-trailer noticed the trailer was not sitting as expected. The driver was able to stop the vehicle without the trailer disconnecting.
In the third incident in February, a driver doing a walk around check found a crack that had the potential to “fail catastrophically”, Basher said.
NZTA issued two safety alerts in February related to the incidents, covering almost 3000 truck trailers.
One of the alerts said several recent failures have been identified in both drawbeams and drawbars certified by Peter Wastney Engineering Ltd.
A visual inspection needed to be carried out, if no signs of failure were found, it was recommended the drawbeam/towbar/drawbar be replaced or recertified as soon as possible, NZTA said in Q&A advice. That may involve re-strengthening.
Stuff approached Peter Wastney Engineering Ltd for comment but this was declined.
The second alert covers skid plate failures on all refrigerated semi-trailers.