A Straddle Carrier suffered a major stability incident at a Terminal when it ran over a pothole and immediately went into full lock, thus resulting in a stability event as the machine turned suddenly. The Carrier was removed from service immediately and a full investigation took place to establish the immediate and direct causes.
The operational area was closed off immediately and potholes repaired.
The Operator did not require immediate medical attention but suffered muscular difficulties for two weeks beyond the incident subsequently returning to full duties.
What went wrong:
This was a direct result of the failure of a Potentiometer which caused the emergency brake and full lock to be applied at same time.
Other contributory factors,
The Carrier had been purchased four years earlier second hand with over 45000 hours of recorded use – the Potentiometer was an original part.
Mechanical shock through contact with Potholes evident at the location of the incident may have triggered the sudden Potentiometer failure.
Lessons Learned / Actions Taken:
- Surface conditions: a two weekly inspection programme has commenced
- Potentiometer failure: the failure was replicated as part of the investigation and information communicated to others in the company group operating similar equipment
- Similar equipment by type removed from service in certain group company locations
- Gap analysis project commenced in terms of Straddle Carrier safety and control features
- An identified requirement for a higher degree of harmonisation on plant standards across the group
- Recognition that despite maintenance being up to date parts can fail
Purpose and Acknowledgements:
The PSS Safety Alert system intends to flag accidents / incidents directly to members to enable them to take onboard any necessary learning or developments.
PSS are grateful to Peel Ports for sharing the information at the base of this Safety Alert, the Peel Ports Lessons Learned presentation is attached.