Emergency during a power failure
You are slewing a 5 t bundle at 10 m radius when the crane loses power. The load is over a walkway, about 4 m above the deck, and the boom is at 60 degrees. The crane has a load-holding brake and a manual lowering system, but the manual pump handle is stored in the cab and the procedure is in the cab pocket. Two workers are on the walkway below, and one is walking toward the load. Wind is light. The supervisor is 80 m away and out of sight.
1. State your immediate actions in order and explain the reasoning behind each.
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First, warn the people below. Sound the horn if it has battery or air reserve, and shout or use the radio to tell the workers to clear the walkway and stay out from under the load. This is the highest priority because the load is suspended over people.
Second, secure the controls. Place all controls in neutral, apply the brake, and do not touch anything that could release the load-holding brake until you understand the system. The load-holding brake should hold the load; confirm it is holding and that the load is not drifting.
Third, keep the area controlled. The exclusion zone must stay until the load is landed. The supervisor is out of sight, so use the radio to report the power failure and the suspended load, and ask for the area to be cleared.
Fourth, follow the manufacturer's manual-lowering procedure. Retrieve the procedure and handle, and lower the load only when the walkway is clear and a dogger is directing. Lowering blind over people is not acceptable; if the area cannot be cleared, hold the load and keep the zone until it can.
Do not attempt to slew or boom down under gravity without the procedure; uncontrolled movement is the main risk.
2. What should have been in place before the lift, and what would you record afterwards?
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Before the lift: a lift plan that identified the walkway as a live area, a controlled exclusion zone under the slew path, and a communication method with a signaller who could see the load and the landing point. The manual-lowering procedure and handle should be checked at pre-start, not discovered mid-emergency. The power-failure procedure should be part of the pre-start check and the operator should know it.
Afterwards, record the event: time, load, radius, boom angle, what failed, the actions taken, the duration the load was suspended, and who was exposed. Report it as an incident, preserve the crane's fault logs if any, and do not return the crane to service until the power failure is diagnosed and the load-holding and lowering systems are function-tested. Review the lift plan and the exclusion zone controls with the crew.