Pre-Shift Inspection Findings on a Rough-Terrain Crane
At the start of a shift, the operator of a 30-ton rough-terrain crane performs the pre-operational inspection. On the 6x19 IWRC boom hoist rope, the operator finds six broken wires randomly distributed within one lay, plus one broken wire at a valley between strands. The boom hoist sheave has a worn groove with sharp edges and a visible ridge; the wire rope sits about 1/16 in. below the sheave flange. A hydraulic hose for the outrigger circuit is chafed through the outer cover to the reinforcement, but no oil is leaking. The anti-two-block warning horn does not sound when the operator manually lifts the weight. The load moment indicator displays normally. The crane is needed for a 7:00 a.m. pick, and the supervisor asks whether the crane can be used for “just one light lift” while a replacement rope is ordered.
1. Which findings are removal-from-service items, and which, if any, could be deferred? Explain the basis.
Read the worked answer
The boom hoist rope is a removal item. For a 6x19 running rope, six randomly distributed broken wires in one lay meets the removal criteria, and the valley break and the sheave condition make the rope condition worse. The worn sheave with sharp edges and a ridge is also a removal item because it damages the rope and indicates the groove no longer supports the rope properly; the rope sitting below the flange is further evidence of wear. The chafed outrigger hose is a removal item even without leakage because the reinforcement is exposed and the hose can fail under pressure. The inoperative anti-two-block warning horn is a removal item because it is a required safety device and must function before operation. The normal LMI display does not override these defects. None of these findings should be deferred for “one light lift.”
2. What must be done before the crane returns to service, and what records or verification are needed?
Read the worked answer
The crane must be taken out of service until the defects are corrected. Replace the boom hoist rope in accordance with the manufacturer’s instructions, inspect and replace or repair the sheave, replace the chafed hydraulic hose, and repair the anti-two-block system. After repair, a qualified person should inspect the affected components and the operator should perform a function test of the anti-two-block, the LMI, the boom hoist, and the outrigger circuit. The repairs and tests should be documented, and the crane should not be released until the inspection confirms that the safety devices operate correctly. The supervisor’s schedule pressure does not change the removal criteria.
3. If the supervisor insists the crane is needed, what is the operator’s response under operator responsibility?
Read the worked answer
The operator should refuse to operate the crane and explain the specific defects: the rope meets removal criteria, the sheave is damaging the rope, the hose reinforcement is exposed, and the anti-two-block is inoperative. The operator has the authority and responsibility to stop work when equipment is unsafe. The correct response is to document the findings, notify the supervisor and maintenance, and request a replacement crane or repaired equipment. Operating “just one light lift” would not be acceptable because the defects affect boom hoist integrity and safety-device function, and a light load does not eliminate the risk of rope failure or two-blocking.