Some lifts you can plan on the back of a method statement. Others involve tandem cranes, tight ground tolerances and a load that costs more than the crane itself. Complex crane lift planning is what turns that second category into a controlled, predictable operation rather than a gamble on the day.
This guide walks through the planning process step by step, from the first site survey to the sign-off on the lift plan. It sits within our contract lift services, where we take responsibility for the whole lift under BS 7121. If you're a project manager, site agent or Appointed Person weighing up how a complex lift comes together, this is what good planning looks like.
What makes a lift 'complex'?
Not every heavy lift is complex, and not every complex lift is heavy. Under BS 7121, a lift is usually classified as complex when it involves higher risk or more variables than a basic or standard lift.
Common triggers include:
- Two or more cranes lifting the same load (tandem or multi-crane lifts)
- Loads with an uncertain or shifting centre of gravity
- Lifting over live roads, railways, occupied buildings or the public
- Restricted access, poor ground conditions or limited setup space
- Proximity to overhead power lines or other services
When a lift is classed as complex, the planning has to go deeper. The Appointed Person leads that work.
The Appointed Person's role
The Appointed Person (AP) is the competent individual responsible for planning the lift and making sure it's carried out safely. On a complex lift, the AP isn't a box to tick. They own the plan.
The AP assesses the risks, selects the right crane and equipment, produces the lift plan and method statement, and confirms everyone on site understands their part. On a contract lift, we supply the AP as well as the crane, so responsibility for planning and execution sits with us, not your team.
That matters when you're already carrying enough compliance risk on a live site.
Step-by-step: how a complex lift comes together
Step 1: Site survey and access planning
Everything starts on the ground. We survey the site to check crane positions, access routes, headroom, and any obstructions such as overhead lines or nearby structures.
We measure the space you actually have, not the space on the drawing. Access for the crane, the load and any support vehicles all gets checked before anything is booked.
Step 2: Ground bearing assessment
A crane is only as safe as the ground beneath its outriggers. We work out the loads the crane will impose and compare them against what the ground can take.
Where the ground can't cope, we specify crane mats or spreader systems to distribute the load. Get this wrong and you risk the crane settling or overturning, so it's never left to guesswork.
Step 3: Load and rigging assessment
Next we confirm the weight, dimensions and centre of gravity of the load. We select lifting accessories rated for the job, and check every item is within its LOLER inspection date.
For awkward or asymmetric loads, the rigging arrangement is planned in detail so the load stays balanced and controlled throughout the lift.
Step 4: Crane selection and outreach
With the load and site data in hand, we choose the crane. The key figure is capacity at radius: how much the crane can safely lift at the outreach the job demands, in metres, not at its maximum rating.
We match the crane to the heaviest pick at the furthest reach, with a safe margin built in.
Step 5: 3D lift modelling
For tandem lifts and tight sites, we use 3D modelling to visualise the lift before anyone turns up. Modelling shows crane positions, load paths, clearances and any clash points against real site geometry.
It lets us test the plan and resolve problems on screen rather than on the day, when a mistake costs time and money.
Step 6: The lift plan and method statement
All of this comes together in the lift plan and method statement. The plan sets out the sequence, the equipment, the ground preparation, the exclusion zones and the roles of everyone involved.
It's a working document the whole team can follow, not paperwork filed and forgotten.
Tandem and multi-crane lifts
When one crane can't do the job, two or more share the load. Tandem lifts add real complexity because the load can shift between cranes as it moves.
Planning covers how the load is split, how the cranes move together, and how the lift is controlled by the crane supervisor throughout. Clear communication and a rehearsed sequence keep both machines inside their safe working limits.
Why detailed planning pays off
Poorly planned lifts lead to delays, safety risks and costly mistakes. A load dropped, a crane on unstable ground or a missed clearance can stop a whole site.
Thorough planning removes those unknowns before the crane arrives. You get a lift that runs to schedule, stays compliant, and doesn't become the reason your programme slips.
That's the point of complex crane lift planning: not more paperwork, but fewer surprises.
