Crane operation
Crane operation is what an operator does every shift: assess the lift, set the machine up, confirm capacity, control the load through the move, and shut down safely. The exam tests capacity-and-radius judgement, correct use of the rated capacity indicator (RCI), signal and communication discipline, and knowing when to stop the job.
Pre-lift checks
- Load: mass, centre of gravity, lift points, condition.
- Path and landing area: ground, underground services, overhead lines, people.
- Pre-start inspection: ropes, hook and latch, brakes, outriggers, limiters, anti-two-block, RCI, logbook.
- Test the RCI and hoist brake at the start of each shift, and report defects rather than working around them.
Capacity is not static
Rated capacity is read at the actual radius, from the chart that matches the configuration: outrigger spread, counterweight, boom or jib, quadrant of slew, and wind allowance. Radius runs from the slew centre to the load line. Boom deflection, load swing and outrigger settlement all increase radius once the load leaves the ground, so a lift planned at 92% of capacity can pass 100% by the time it clears a truck tray.
Signals and control
One designated signal person, standard hand signals or an agreed radio protocol, and an emergency stop signal that any person may give. Smooth single-function movements: no shock loading, no dragging, no side pulls outside the chart, and tag lines operated from outside the danger zone.
Worked example
A 12 t load plus 0.4 t of rigging is 12.4 t. The chart gives 15.0 t at 10 m and 12.0 t at 12 m. The plan says 10 m, but after lift-off the operator booms out to clear a fence and reaches 12 m: 12.4 / 12.0 = 103% of rated capacity. The load must be set down and the lift re-planned from a closer position. The RCI alarm is a backstop, not a working limit.
Traps that cost marks
- Reading capacity at the planned radius instead of the worst radius during the move.
- Using the wrong chart: over-the-side versus 360 degrees, on-rubber versus outriggers.
- Deducting the hook block but forgetting rigging, or vice versa.
- Accepting signals from several people at once, or moving on an unclear signal.