Lift Planning
Lift Planning on the NCCCO Lattice Boom Truck (LBT) exam tests whether you can turn a load weight and a boom configuration into a defensible capacity check using the manufacturer's load chart, then document the plan.
Capacity is gross, not net
Lattice boom truck charts give gross capacity for a specific boom length, jib length and offset, counterweight, outrigger spread, quadrant, and radius. Deduct everything hanging below the boom tip that the chart note does not already include: headache ball or hook block, slings, shackles, spreader bars, stowed jib, auxiliary sheave, and any attached rigging. Net capacity is what remains. Never subtract from the load; always subtract from the chart's gross capacity.
Radius and configuration
Radius is measured from the center of rotation to the vertical load line at the boom tip, at the loaded condition. Boom deflection, load sway, and boom attitude change radius. Use the boom length actually pinned, not a nearby chart column, and do not interpolate between boom lengths unless the manufacturer permits it. Verify the quadrant: over the side, over the front, or 360-degree charts are not interchangeable.
Worked example
An 80 ft boom, 30 ft radius, over-the-side outrigger chart shows 24,000 lb gross. Deductions: 1,000 lb hook ball + 400 lb slings = 1,400 lb. Net = 22,600 lb. A 20,000 lb load uses 20,000/22,600 = 88.5% of net capacity. Above a 75% critical-lift threshold, the plan needs engineering review, a pre-lift meeting, and a documented alternate path.
Traps
Using the on-rubber chart while set on outriggers; forgetting a stowed jib deduction; measuring radius to the load's edge; mixing boom-length columns; and ignoring boom deflection at long radius.