Why Most Crane Accidents Begin Long Before the Hook Moves
Accident investigations across the lifting industry tell a remarkably consistent story: overturned cranes, power-line contacts, and dropped loads are rarely caused by the machine itself. They are caused by decisions made hours or days earlier — a load weight that was estimated instead of verified, a working radius that grew on site beyond what was assumed, an outrigger set down on a backfilled trench nobody checked. A lift plan is the engineering control that converts every one of those assumptions into a verified number before the crane is even mobilised.
The first act of planning is classifying the lift. A routine lift — a known load, comfortably within the crane's capacity, in a clear area — still needs a documented plan, but a standard one. A lift becomes critical when it approaches the machine's limits or raises the consequence of failure: common triggers are any lift exceeding roughly 75 percent of the crane's rated capacity in its working configuration, tandem lifts shared between two cranes, lifts over live plant or occupied structures, blind lifts where the operator cannot see the load, and any lifting of personnel. Critical lifts demand a dedicated engineered plan, a formal review, and usually a permit to work — a discipline embedded in international standards such as ASME B30.5 and BS 7121, and one that major project owners across the Kingdom now expect as standard practice.
Treat the plan as a productivity tool, not paperwork. The same exercise that keeps the crane standing also selects the right capacity class the first time, fixes the pick and set positions so the crane mobilises once instead of twice, and sequences deliveries so a machine billed by the day is never waiting on a load that is not ready. On tight urban sites in Riyadh, Jeddah, or Dammam, the lift plan is often the difference between a two-hour operation and a two-day one.
Step 1: Know Exactly What You Are Lifting — Weight, Centre of Gravity, and Gross Load
Everything in a lift plan flows from one number: the true weight of the load. Get it from the most reliable source available — the manufacturer's nameplate, certified shipping documents, a weighbridge ticket, or fabrication drawings with the engineer's calculated weight. If the weight must be calculated from drawings or material take-offs, add a contingency of around 10 percent, because welds, coatings, trapped water, and site modifications all add mass that never appears on paper. What a lift plan can never accept is a weight guessed by eye — fabricated steel, filled vessels, and wet concrete elements are notorious for weighing far more than they look.
The second property is the centre of gravity. The crane hook must sit vertically above the load's centre of gravity before the load leaves the ground; if it does not, the load will tilt, swing sideways at lift-off, and shock-load the rigging. For symmetrical loads the centre is where you expect it, but tanks with internal fittings, skid-mounted equipment, and precast elements with block-outs are often heavier at one end — check the drawings for marked CG points and use the designed lifting lugs wherever they exist. If the CG position is uncertain, plan an incremental trial lift to find balance before committing.
Finally, plan around the gross load, not the net one. The crane's chart capacity must carry the load plus everything between it and the boom tip: the hook block — several hundred kilograms on mid-size mobile cranes, and potentially more than a tonne on the 100-ton-plus classes — plus slings, shackles, and any spreader beam or lifting frame. On a lift working close to the chart limit, half a tonne of forgotten rigging can silently consume the entire safety margin. List every component with its weight in the plan, and carry the total — not the payload alone — into the crane selection step.
Step 2: Select the Crane from the Load Chart, Not from the Model Name
A crane's nominal tonnage is a naming convention, not a promise. A "50-ton" crane lifts 50 tons only at its minimum radius, with a short boom, over its most stable quadrant; move the same machine's hook out to a 20-metre radius and the chart allowance can drop below 10 tons. Radius — the horizontal distance from the crane's slew centre to the hook — is the single variable that dominates capacity, so the plan must fix the worst-case radius across the whole operation: the pick position, the set position, and every point the load swings through in between.
With the radius, the required hook height, and the gross load known, the crane is selected by reading the load chart for a specific configuration — boom length, counterweight, and outrigger spread — never from the model name. Chart ratings assume outriggers fully deployed on firm ground, the crane level to within about one percent, and calm conditions; mobile hydraulic cranes are typically rated at no more than 85 percent of their actual tipping load, and that structural and stability margin belongs to the manufacturer, not to your load. Sound practice keeps the planned gross load at or below 75 to 80 percent of the chart figure for the working configuration — which is also the threshold at which many owners reclassify the lift as critical.
As broad guidance across common Saudi site work: the 25-ton class handles truck unloading, scaffolding material, and light steel at short radius; the 50-to-70-ton classes cover most mid-rise construction lifting — AC packages, precast wall panels, formwork tables, and rebar bundles at moderate radius; and the 100-to-160-ton classes come into play for long-radius work over existing structures, heavy precast beams, tanks, and plant equipment. These are starting points only: the final selection must always be confirmed against the exact chart of the specific crane and configuration that will arrive on site — which is precisely the check our team runs with you before mobilisation.
Step 3: Engineer the Ground and the Set-Up — Outriggers, Mats, and Site Hazards
The load chart assumes something the site must earn: ground that can carry the crane. During a slew with a full load, the crane's weight transfers dramatically, and a single outrigger can momentarily carry a large share — plan conservatively for up to about 80 percent — of the combined weight of the crane, its counterweight, and the load. Divide that outrigger force by the area of the mat beneath it and you have the bearing pressure the ground must resist. Then compare it with what the ground can actually take: well-compacted engineered fill and firm native soils carry far more than loose sand, while recently backfilled areas and sabkha ground may carry very little. Wherever pressure exceeds capacity, the answer is engineered mats or steel plates that spread the load — sized by calculation, not by whatever timber happens to be lying around.
Set-up geometry is equally strict. The crane must be levelled to within about one percent of grade, because even a few degrees of lean introduce side loading on the boom and can strip away a large share of the chart capacity at long boom lengths. Outriggers must be fully extended exactly as the chart configuration requires — an outrigger left half-extended on the "unused" side is one of the oldest causes of tip-overs in the industry. Keep the set-up clear of excavation edges by a horizontal distance at least equal to the excavation depth, and more in loose or disturbed soil; and before positioning, verify what lies underneath: buried utilities, old septic tanks, culverts, and basement slabs have all collapsed under outrigger loads that the surface showed no sign of.
Overhead, the discipline is absolute. Treat every power line as live, maintain at least three metres of clearance from distribution lines up to 50 kV and considerably more for high-voltage transmission lines, and where work must happen near lines, assign a dedicated spotter with no other duty and agree the boom's limit positions before the first lift. In the plan, mark power lines, adjacent structures, public roads, and pedestrian routes on the lift drawing — the sketch takes minutes and forces every conflict into the open.
Step 4: Rigging — Where Geometry Quietly Multiplies the Load
Rigging is where simple geometry quietly multiplies forces. With a two-leg sling, the tension in each leg depends on its angle to the horizontal: at 90 degrees — legs vertical — each leg carries half the load; at 60 degrees each carries about 58 percent; at 45 degrees about 71 percent; and at 30 degrees each leg carries tension equal to the full weight of the load. A four-tonne load rigged with shallow legs can put four tonnes into each sling. That is why good practice keeps sling angles at 60 degrees or steeper wherever possible, treats 45 degrees as the working minimum, and prohibits anything below 30 degrees outright. Where the load is long and steep angles are impossible, a spreader beam restores vertical legs — at the cost of its own weight, which goes straight back into the gross load.
Every rigging component must carry a legible working load limit (WLL) tag or marking, and the WLL must be checked against the calculated leg tension — not against the load weight. Inspect before every lift: wire rope slings for broken wires, kinks, crushing, and corrosion; webbing slings for cuts, abrasion, and chemical damage — especially relevant under the Saudi sun, where UV degrades synthetic slings faster than most crews expect; shackles for bent pins and stretched bodies, with pins fully seated and never replaced by ordinary bolts. Use softeners or corner protectors wherever a sling passes over an edge, because a sharp steel corner can cut a loaded sling almost instantly.
Finally, control the load itself. Attach taglines of sufficient length so workers guide rotation from outside the fall zone — never with hands on a suspended load; hooks must carry safety latches, closed and functioning; and the rigger who assembled the arrangement should be the one who confirms it against the plan before the signaller clears the lift.
Step 5: Execute the Lift — One Team, One Signaller, One Trial Lift
A lift plan is executed by named people, not job titles on a form. The lift supervisor owns the plan on the day and holds authority to stop the operation; the operator must be certified on that crane class and briefed on the specific chart configuration; the rigger certifies the sling arrangement; and one — exactly one — designated signaller directs the operator, using standard hand signals or a dedicated radio channel with a clear protocol. The single-signaller rule exists because divided instructions during a slew are how loads end up where nobody planned them. Before the first pick, a toolbox talk walks the whole team through the plan: the weights, the radius limits, the exclusion zone, and the abort criteria.
Then comes the cheapest safety device in the industry: the trial lift. Raise the load 100 to 200 millimetres and hold. Check the load moment indicator (LMI) reading against the predicted gross weight — a significant discrepancy means the weight assumption is wrong, and the lift stops there, on the ground, where the mistake costs nothing. Check that the crane stays level, that the brakes hold, and that the slings are seated with the load hanging without tilt. Only when everything matches the plan does the load go higher. Throughout the lift, the exclusion zone under and around the swing path stays barricaded and empty — suspended loads never travel over people.
Weather is part of the plan, not a surprise. Most mobile crane manuals cap standard lifting at wind speeds around 9 to 10 metres per second — roughly 32 to 36 kilometres per hour — and the limit drops sharply for loads with large sail area such as cladding panels, formwork tables, and shutters. On Saudi sites, afternoon winds pick up fast and a dust storm can end visibility within minutes, so the plan should name the wind limit, the instrument that measures it (the crane's anemometer or a handheld unit at height), and the person who calls the stand-down. Every member of the team holds stop-work authority; a lift that pauses costs an hour, while a lift that continues into doubt can cost the project.
Plan Your Next Lift with Tahalof Al-Khair
A strong lift plan deserves a crane that matches it. Tahalof Al-Khair Equipment & Transport operates XCMG cranes exclusively, from 25 to 160 tons, delivered with certified operators, comprehensive insurance, and load charts for the exact configuration you are planning against — backed by a fleet of more than 472 owned machines maintained in-house with genuine parts, 24/7 delivery to every region of the Kingdom, and rental terms from daily to yearly.
Share your load weight, working radius, and site conditions with our team, and we will help you match the right crane class and configuration before mobilisation. Message us on WhatsApp at +966 59 516 5509 or email info@tac-rentals.sa for a fast quotation.
Request this equipment
Tell us the site and the duration — we'll confirm availability and a tailored rate.
Request a Quote