NCCO common mistakes
NCCO · Understand the traps and how to avoid them.
Reading the capacity from the load chart for the boom length and radius at the start of the lift and then continuing to use that single number after the boom is telescoped out or the load is swung to a longer radius, instead of re-entering the chart at the actual working radius for each configuration.
Candidates memorize one 'capacity for this setup' figure during the pre-lift briefing and treat the chart as a lookup table rather than a continuous constraint. The chart's rows differ by boom length and the deduction lines for jib, stowed attachments, and reeving are easy to skip under time pressure, so the number feels fixed.
What to do instead
Work the chart as a procedure, not a lookup: for each lift step record boom length, boom angle, radius, and configuration, then read the intersection and subtract every applicable deduction (jib, auxiliary head, stowed lattice, block and rigging weight). Re-verify the chart any time radius, boom length, or configuration changes mid-lift, and state the governing radius out loud during the pre-lift plan.
Treating the load chart's rated capacity as the allowable load and ignoring that rigging and below-the-hook hardware weight must be subtracted from it, so the hook load exceeds the chart value while the candidate believes they are within limits.
The chart number is the most visible figure on the page, and sling, shackle, and block weights are small relative to capacity, so candidates mentally round them away. The distinction between gross load and net load is learned as vocabulary but not applied arithmetically.
What to do instead
Compute gross load explicitly: payload plus all slings, shackles, spreader beams, and the hook block if the chart requires it. Compare gross load to chart capacity and keep the arithmetic on the lift plan. Practice with a worked example where the rigging weight alone pushes a near-capacity lift over the limit.
Determining sling tension using the load weight divided by the number of legs, without applying the horizontal angle factor, so a two-leg choke or basket arrangement at a shallow angle is treated as sharing load equally.
Equal sharing is intuitive and true only for vertical legs. Candidates who have not internalized the tension formula treat the sling angle as a rigging detail rather than a multiplier, and shallow angles look safer because the slings appear less stressed.
What to do instead
Use tension equals load divided by the number of legs times the sine of the horizontal angle (or the load-angle factor from the rigging card). Drill the factor for 60, 45, and 30 degrees until the multiplier is automatic, and always state the sling angle on the rigging plan before selecting sling capacity.
Selecting shackles, hooks, and slings by eyeballing size or matching the color code without confirming the working load limit against the marked rating and the configuration (side loading, choke reduction, basket efficiency).
Hardware is familiar and looks overbuilt; color codes are memorable and easy to substitute for reading the stamp. Candidates also forget that a choke reduces sling capacity and that side-loading a shackle lowers its rating.
What to do instead
Read the actual marking on every component and compare it to the calculated tension, not the payload. Apply configuration derating factors (choke, basket, side load, included angle) before accepting the component, and reject any hardware with illegible or missing markings.
Skipping or shortening the pre-operational walk-around, particularly the load moment indicator or rated capacity limiter calibration check, the anti-two-block function test, and the outrigger or mat bearing verification, because the crane started fine and the last operator reported no issues.
Shift-start pressure and familiarity with the machine make the checklist feel like paperwork. Functional tests of the limiter and anti-two-block require deliberate action and are the first items dropped when the crew is waiting.
What to do instead
Run the inspection as a fixed sequence with a signed checklist: visual walk-around, fluid and structural checks, then functional tests of the LMI/RCL, anti-two-block, and outrigger setup before any load. Treat a failed or unverified limiter as a no-lift condition, not a note for later.
Setting up with outriggers on undisturbed-looking fill, near a utility trench, or on a slope without mats, and accepting the setup because the floats 'look level' rather than verifying bearing pressure and ground conditions.
Ground failure is invisible until it happens, and level appearance is mistaken for stability. Candidates underestimate how concentrated outrigger reaction forces are and how far a trench's influence zone extends.
What to do instead
Verify ground bearing capacity against the crane's outrigger reaction figures, use mats sized for the pressure, keep floats clear of excavations by at least the required distance, and confirm level within the manufacturer's tolerance. If bearing capacity is unknown, treat it as inadequate until proven otherwise.
Relying on radio communication without a fallback and without confirming that the signal person and operator share the same channel, call signs, and stop signals, then continuing the lift when radio contact breaks.
Radio feels continuous until it isn't, and crews assume the person on the other end is the designated signal person. Candidates also forget that any person may give a stop signal and that the operator must obey it.
What to do instead
Establish at the pre-lift meeting: designated signal person, channel, standard hand signals as backup, and the rule that loss of communication means stop and hold. Confirm radio function before the lift and rehearse the emergency stop signal.
Treating the load as a rigid, static weight and failing to account for swing, wind, and dynamic amplification when starting or stopping a travel or hoist motion, resulting in a capacity or control surprise mid-lift.
Load charts are static tables, and candidates extrapolate that static number to a moving load. Wind area on a large sail-like load and the surge from sudden deceleration are not visible on the chart.
What to do instead
Plan lift speed and tag line control to avoid shock loading, check wind speed against the manufacturer's limit and the load's sail area, and apply the dynamic/allowable margin the chart or site procedure requires. Brief tag line handlers on controlling rotation before the load leaves the ground.
Responding to an unexpected load moment alarm, two-block warning, or power loss by continuing or improvising a control input instead of executing the defined emergency lowering or shutdown sequence.
Alarms during a lift are stressful and the instinct is to finish the move quickly. Candidates have read the emergency procedure but never rehearsed which controls to use and in what order when the limiter engages.
What to do instead
Know and rehearse the specific sequence: stop the motion, assess, lower the load using the permitted override or emergency lowering procedure only as the manufacturer allows, and never bypass a limiter. Practice the sequence in a controlled setting so the first execution is not during an incident.
Answering regulatory and responsibility questions from general safety intuition rather than citing the specific duty: pre-lift planning, qualified rigger and signal person requirements, load chart compliance, and the operator's authority to stop an unsafe lift.
The standards overlap and candidates blur them into generic 'be safe' answers. The operator's stop-work authority and the employer's inspection and maintenance obligations are frequently tested and frequently answered vaguely.
What to do instead
Study the standards by duty holder: what the employer must provide, what the operator must verify, what the rigger and signal person must be qualified to do, and when a lift requires a documented plan. Practice answering with the specific obligation rather than a general principle.