Operating plant equipment to specification (machine-specific competences)
This domain is about operating the machine you are competent for, within the limits set by the manufacturer and the site, and applying machine-specific technique rather than brute force.
Core rules
- The operator's manual and the load or capacity chart define the specification. Rated capacity, maximum gradient, permissible attachments, tyre or track limits and travel speeds all come from there, not from habit.
- Stability depends on ground and geometry. Soft ground, backfilled trenches, recently disturbed ground and slopes all reduce capacity. Surcharge from spoil or tracked plant near a trench edge reduces bearing capacity further.
- Tracked excavator travel on a slope - bucket low and on the downhill side, drive sprockets to the rear (uphill), slew lock engaged, low speed, no slewing while travelling.
- Never work beyond the machine's envelope. No using the bucket as a battering ram, no lifting with a bucket tooth, no dragging loads sideways with the boom.
- Keep the structure clear of obstacles - tail swing and counterweight radius cause struck-by and crush incidents; establish the slew zone before you start.
- Attachments matched to task - the right bucket or blade for the material, correct tooth condition, and no adapted or uncertified attachments.
Worked example
You are digging a 2.2 m trench and the spoil is being placed about 0.8 m from the edge. You move the spoil back to at least 1 m and check that the spoil heap is not creating a fall hazard. Reasoning: spoil within a metre adds a surcharge close to the excavation lip and can trigger collapse, so the trench edge is loaded exactly where support is weakest. You then confirm the batter or support system with the supervisor.
Traps that cost marks
- Quoting a headline capacity figure instead of the chart value at the actual radius and height.
- Assuming dry weather means firm ground under a tracked machine.
- Slewing over people, trenches or the site boundary because "it was quicker".
- Operating a machine outside your carded category and calling it experience.