Pre-Start Checks After a Night Shift
You are the first operator on shift on a 360° excavator that was used until 22:00 the previous night. The machine is parked on level hardstanding. On your walk-round you notice: a small pool of oil under the boom ram, a track that looks slack on the left side, a cracked bucket tooth, and a missing rear-view mirror on the right. The daily inspection sheet from the night shift is signed and shows no defects. The engine starts and all gauges read normal. Your first task is a 3-hour bulk excavation in a confined area with a banksman and two groundworkers.
1. Decide which findings stop the machine and which allow it to work, and justify each.
Read the worked answer
Stop-work findings:
- Oil under the boom ram - a leak on a hydraulic ram is a potential sudden failure and a fire/slip hazard. It must be investigated before work; a weep may be acceptable if it is a known minor seep and the level is maintained, but a pool is not. Do not work until the source is identified and the defect assessed.
- Cracked bucket tooth - a tooth can detach under load and become a projectile into the excavation or at a groundworker. The bucket must not be used until the tooth is replaced. This is a stop.
- Missing right rear-view mirror - the machine's all-round visibility is compromised, and you will be working in a confined area with two groundworkers. This is a stop until the mirror is replaced or an alternative (e.g. a spotter on that side, or a camera) is confirmed - but the mirror is the correct fix.
May proceed (with monitoring):
- Slack left track - adjust to the manufacturer's spec before work; a slack track can derail, especially in a confined area with tight turns. Treat as a defect to correct, not necessarily a stop if adjustment is straightforward.
The signed sheet is not evidence - the night shift signed 'no defects' against visible faults, so the inspection regime is not working. Report that as a system failure, not just a machine defect.
2. The night-shift sheet says no defects, yet you have found four. What does this tell you, and what should you do about it?
Read the worked answer
It tells you: the pre-use inspection is being treated as paperwork, not a check. Either the night operator did not walk round, or did not know what to look for, or felt pressure to sign and go. Any of these is a safety-culture problem that will recur.
What to do:
- Do not sign the sheet as correct - record the actual defects, the time found, and that they were missed by the previous shift.
- Report to the supervisor and enter the defects in the defect log; tag/isolate the machine as required for the stop-work items.
- Do not work the machine until the stop items are cleared.
- Raise the inspection issue - ask for the night operator to be briefed, and for the inspection to be verified (e.g. supervisor spot-checks, or a second signature).
- Consider the wider implication - if the sheet is unreliable, other machines may also be signed off with defects. Suggest a check of the other plant on site.
Why: The purpose of the pre-use check is to find exactly these faults before they cause an incident. A false 'no defects' signature removes the control entirely, so the response must address the system, not just this machine.