‘Piles of broken bolts should have rung alarm bells’ for First Glasgow, says TC Rooney
The two companies that make up First Glasgow have escaped with a warning after a bus crash caused by faulty anchor spring bolts on an ADL Enviro300.
First Glasgow (No. 1) and First Glasgow (No. 2), with a combined vehicle authorisation of 1,055 vehicles, have given an undertaking to review their transport management systems.
The two companies appeared before Traffic Commissioner (TC) Kevin Rooney at an Edinburgh Public Inquiry following the crash in April 2018, in which the bus was extensively damaged and passengers and the bus driver were injured.
When the vehicle was examined by DVSA it was found that both nearside and offside rear anchor spring bolts were broken. A check of the vehicle maintenance records found that the vehicle had six rear spring anchor bolts fitted during the previous six months. The shortest time between bolt replacements was seven days.
Breakages since 2013
A fleet check showed that inspections were focused on the suspension components of ADL Enviro300 vehicles. Sixty vehicles were inspected and seven immediate prohibitions issued for broken rear spring anchor bolts.
Checks of the records showed that five of the seven prohibited vehicles had broken rear spring anchor bolts recorded on the previous inspection reports. Further investigation found that rear spring anchor bolts had been breaking on the ADL Enviro300s since 2013 when the vehicles were introduced.
Since then First Glasgow had purchased 647 bolts from ADL for a fleet of approximately 130 vehicles. First Glasgow had not informed DVSA of any specific problems with the anchor bolts.
Prior to the crash, the safety inspection programme had not been enhanced as a result of the large number of bolt breakages. In response to the DVSA findings, the inspection frequency was tightened for ADL Enviro300 suspension components initially to fortnightly and then later to weekly.
Vehicle Examiner George McIntyre said that the maintenance arrangements generally were satisfactory. He had never seen rear spring anchor bolts fail in that way on any vehicle before. It should have been ringing alarm bells.
The broken spring anchor bolts were a safety critical defect. The defect had only been witnessed on Enviro300 vehicles, not the smaller Enviro200. He accepted the advice issued by ADL in 2011 was in relation to the failure, or potential failure, of the spring mounting bracket rather than the bolt.
Issues tracked
Engineering Director Gary West said that he believed there were around 1,000 Enviro300 vehicles in the wider bus industry.
In relation to the apparently high number of replacement bolts purchased in 2016, he said the issue was that bolts would be replaced routinely whenever a bush or spring was replaced so it was not apparent from the face of the figures that the component had a malfunction.
He accepted that, with the benefit of hindsight, DVSA should have been involved earlier. However there had never been any loss of control or stability of any vehicle. The issue was now more serious than previously thought. There was a new engineering management IT system, Tracerit, which tracked engineering issues.
He did not think that the defect was safety-critical but it was safety-relevant. There was no industry guidance on notifying DVSA. Broken bolts had become the norm and had become unremarkable. There was now re-education of the internal vehicle examiners.
For First Glasgow, Peter Woodhouse said that the directing mind of the business knew of the general issue but did not know of the migration of the bolts and hence the safety impact. The bolt breakages were seen as annoying and costly, not safety-critical.
It was accepted that there had been a breakdown in communication between the vehicle examiners and senior management. The DVSA guidance on what to report relating to recalls had been accepted by the Agency as inadequate.
‘Not good enough’
Issuing a formal warning of the need constantly to monitor maintenance arrangements and tighten them where evidence indicated concerns, and to ensure that sophisticated management systems did not remove the ability for direct communication, the TC said that he considered that the defect was safety-critical in its own right.
There were secondary risks too, in that the displaced bolt appeared to contact either a wiring loom or air pipes and could cause failure in those items.
However, he accepted that even a broken and significantly displaced bolt would not have manifested itself in the steering or handling of the vehicle. It was only the ultimate failure that would do so.
While such a failure ultimately seemed inevitable, the strengths of the wider First Glasgow maintenance system provide a degree of mitigation.
First Glasgow had the buses with the broken and displaced bolts. The prohibitions should have been properly investigated. They clearly were not. First Glasgow wilfully and recklessly failed to make such inquiries as an honest and reasonable man would make.
First Glasgow had, in 2017, identified that there was a problem. It had knowledge of the extent and potential risks arising over and above cost and inconvenience.
It was at that time, at the very latest, that inspection frequencies for the rear suspension should have been tightened significantly. It took DVSA’s intervention for that to happen. That was not good enough.
It was said they complied with, and exceeded in fact, the manufacturer’s advice. However, they held the first-hand evidence that the manufacturer’s advice did not stop the components failing. The advice was patently inadequate.
Comms breakdown
First Glasgow had sophisticated systems in place. It would appear that the sophistication of those systems might be contributory to the failure in respect of these defects. Vehicle examiners answered the questions they were asked.
In a modern process- and data-driven environment, there needed to be a mechanism for team members to point out exceptional matters. The piles of broken bolts should have rung alarm bells. The defects had the potential to cause real harm. It was accepted that communication broke down and that must be put right.
