Anomalies in the magnetic particle inspection procedures likely led to the crack not being detected.
The ATSB acknowledges the proactive safety action taken by Aurizon to address the safety issue but considers that further action, in line with magnetic particle inspection best practice, should be undertaken. The ATSB notes the response provided and that the action initiated by Aurizon, once implemented, should address the safety issue.
Aurizon advised that it has reviewed magnetic particle inspection practices in all of its maintenance facilities, and raised awareness across its staff as follows:
We can confirm that in other locations where we perform or have MPI [magnetic particle inspections] performed the equipment used is similar and that the risk of not overlapping exists in each of these locations. We have reviewed our documentation and we do not (to date) explicitly state that overlapping is required. We have reviewed the practices in all our current locations and can confirm that we have raised awareness across our supply chain. We have also addressed the observed non‑conformance at Rockhampton. We are working to amend processes and procedures to highlight the need to overlap and ensure all our alternative locations are aware of what is expected. Overlapping represents best practice for MPI.
We believe the value of an additional test piece for this application is questionable given the magnetic field is confirmed (lift test) daily and then the equipment is used by a trained operator in a well-lit, dedicated work station with a dedicated probe and a repetitive inspection regime for each wheelset which allows good access for the probe. The testing is expected to be conducted to the Work Instruction which is written/approved/authorised by an…Engineer who has interpreted the requirements of AS1171 as they relate to this task and who has not considered it necessary to introduce a test piece. We would be happy to reconsider but currently do not see any value in its introduction as when a crack is found there is always heightened interest in the work place and additional opportunity for others to repeatedly ensure that they can find the crack, to understand how to make it easily visible and to understand the nature of the cracks we are looking for and how they present.
The…inspection documentation calls for reapplication of the ink and this should have been observed and can be expected to be occurring if the process is being executed to the documentation hence the audit finding/observation is a non-conformance and needs to be rectified/reinforced/toolboxed (as it was) immediately and on an ongoing basis (which it is (supervisors) and confirmed through audit of the various locations now performing this work).
The ATSB acknowledges the safety action taken by Aurizon to improve the effectiveness of magnetic particle inspection. However, it is noted that this does not include requiring the use of test pieces. The use of standard test pieces is an integral part of Australian Standard AS1171 for checking test equipment and the consistency of testing systems. As such, the ATSB considers that it represents best practice and therefore issues the following recommendation.
The Australian Transport Safety Bureau recommends that Aurizon addresses the non-use of standard test pieces during magnetic particle inspection.
On 19 June 2019, Aurizon responded to the recommendation by updating their Magnetic Particle Inspection procedure to include the use of standard test pieces by 30th November 2019. Ongoing assurance will be provided by their existing audit regime, where necessary.
The ATSB acknowledges the prompt and positive response to the recommendation. The ATSB notes the response provided and that the action initiated by Aurizon, once implemented, should address the safety issue.
