Authorities face a logjam of months if not years in the scramble to get urgent safety checks done on hundreds of truck-trailers.
Crack identified on trailer’s drawbar after approximately two years in service. (The alert was issued following the identification of failures in towing connections involving drawbeams and drawbars certified by Peter Wastney Engineering Ltd.) Photo: NZTA
At the same time, more details have emerged of the two trailer failures that sparked the unprecedented safety alert.
The first failure was last August. One of Andrew Havill's drivers with Aratuna Freighters in Greymouth was descending on the Nelson side of the Hope Saddle on SH6, 50km north of Murchison, when the trailer drawbeam snapped off the truck.
"It fatigued and broke off and hit a bank," Mr Havill said.
"One of the team was driving... I just got the call, I couldn't believe it. It wasn't till I got photos ... the penny started dropping [as to] actually what had happened. It was sickening."
The full trailer of the eight axle 48 tonne truck drifted across the opposite lane for 40 metres, into the far bank.
"No, I don't ever want to see that again," Mr Havill said. "We were just very, very lucky in that instance, incredibly lucky."
He had since got his 10 truck-trailers recertified, without finding other problems, though he has had parts of them rebuilt.
Meanwhile, in the Rai Valley to the north, Malcolm Edridge who owns of Mike Edridge Contracting was totally unaware of any problems, until one of his drivers doing a daily walk-around inspection of his truck last month spotted a large crack in the trailer drawbar.
"It had appeared since his inspection the day before," Mr Edridge said.
"Essentially the drawbar could have broken free and the trailer would've went adrift - that could happen any time."
He hadn't seen anything like it in two decades of trucking.
The trailer in question the day before had 25 tonnes of rocks in it, heading through the steep and winding Whangamoa Saddle on SH6 near Nelson.
These two failures sparked an investigation into certifying engineer Peter Wastney of Nelson, leading to his suspension last year and, a month ago, the official order to have all 1500 truck-trailers he'd signed off recertified.
The resulting certification logjam is worst in Nelson - Marlborough and on the West Coast.
Since the safety alert a month ago, just 15 trailers have been recertified according to the Transport Agency - that's 1 percent of the total that need to be.
Most of the extra load is now falling on a single certifier, Lance Hope of Richmond.
He estimated all the Wastney-trailer recertifying will take two years.
"We were busy enough anyway without a certifier dropping out," Mr Hope said.
He and a colleague's workloads doubled when Mr Wastney was suspended, then ramped up again when the safety alert went out.
"Our commitment is to our original clients, so the recertification stuff plays second fiddle."
He had 100 trailers due to undergo a design review, which is the best indication of whether there's any steel fatigue and is the second and final step towards recertification.
But he had not yet done the first step, an initial inspection, on another 100-plus truck trailers, he said.
Malcolm Edridge doesn't even own any other Peter Wastney-certified trailers - but he's still caught up in the jam.
"I've got a new service truck needing certification for a little crane to go on it and I've got two new trucks about to turn up that'll need certified drawbars and headboards ... it's an issue. I've had a truck waiting for three months to get a design done and we're still no further ahead."
Kelvin Barclay, who heads the Heavy Vehicle Certifying Engineers industry group, stresses that even that initial inspection stage is effective at spotting any flaws.
"They can recognise immediately if one is likely to be insufficient or dangerous in any way.
"You get familiar with these items and you just know what looks right and what doesn't - plates too thin, not enough bolts, a whole lot of factors that would be obvious."
The only other heavy vehicle certifier in the region including the West Coast, David Plum of Nelson, has been avoiding the worst of the pressure so far.
The Transport Agency strategy was to look for obvious damage or weaknesses to start with, sort those out, then turn to the rest, he said.
The Transport Agency has called in another certifier from Canterbury, Morgan Boyd.
He would spend a few days each month in Blenheim and the West Coast, beginning after Easter, Mr Boyd said.
Crafar Crouch Construction of Blenheim said the backlog was not a huge inconvenience so long as it could operate its 10 Peter Wastney-certified truck-trailers safely in the meantime.
Some Wastney trailers will be in other parts of the country.
Only 50 or so engineers nationwide are allowed to certify truck towing connections, and Kelvin Barclay said most were very very busy.
Adding to that has been a second safety alert issued last month about cracks in hard-to-spot places discovered in several refrigerated semitrailer towing connections. So far these don't have to be recertified, but the Transport Agency is calling for greater vigilance when drivers check them.
Some industry players are now questioning whether the Agency's auditing of certifying engineers is good enough.
RNZ has asked the Agency to release reports into why the two trailers in Nelson-Marlborough failed.