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High Risk Work Licence - Slewing Mobile Crane C1 (100t) study materials
High Risk Work Licence - Slewing Mobile Crane C1 (100t) study resources

High Risk Work Licence - Slewing Mobile Crane C1 (100t) practice questions

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Question 1Legislative and regulatory requirements, duty of care and standards

Under the model WHS Regulations, which person is primarily responsible for ensuring that a high risk work licence is held by a crane operator before work begins?

  1. The operator's registered training organisation
  2. The site's crane crew spotter
  3. The crane hire company's insurer
  4. The person conducting the business or undertaking (PCBU) Correct answer.

Explanation

The PCBU holds the primary duty of care under WHS law, which includes ensuring that high risk work is only carried out by a person holding the correct licence class. This duty cannot be delegated to the operator, the trainer or an insurer. Verification of the licence is part of the PCBU's obligation to control risks at the workplace.

Question 2Legislative and regulatory requirements, duty of care and standards

A slewing mobile crane with a rated capacity of 100 tonnes is being used. Which high risk work licence class must the operator hold?

  1. C2
  2. C6
  3. C0
  4. C1 Correct answer.

Explanation

Licence classes for slewing mobile cranes are set by rated capacity bands, and the C1 class covers cranes with a rated capacity above 20 tonnes and up to and including 100 tonnes. A 100-tonne crane therefore falls within C1. Operating outside the licensed capacity band is an offence under WHS regulations.

Question 3Legislative and regulatory requirements, duty of care and standards

What is the standard currency period for a high risk work licence in most Australian jurisdictions before renewal is required?

  1. Five years Correct answer.
  2. Two years
  3. One year
  4. Ten years

Explanation

High risk work licences are generally issued for a five-year term, after which the holder must apply for renewal with the regulator. Operators should track expiry dates because an expired licence means the person is no longer licensed to perform the work. Working on an expired licence breaches WHS requirements.

Question 4Legislative and regulatory requirements, duty of care and standards

Who has a duty to take reasonable care for their own safety and that of others affected by their actions on a crane site?

  1. Only the principal contractor
  2. Only the crane operator
  3. Only the safety officer
  4. Every worker, including the crane operator and dogger Correct answer.

Explanation

WHS legislation imposes a personal duty on each worker to take reasonable care for their own health and safety and to avoid adversely affecting the safety of others. This duty applies to operators, doggers, riggers and labourers alike. It sits alongside, not instead of, the PCBU's duties.

Question 5Legislative and regulatory requirements, duty of care and standards

Which document sets out the legal requirement to manage risks associated with crane operations through a hierarchy of control?

  1. The model WHS Regulations Correct answer.
  2. The crane manufacturer's brochure
  3. The Australian Standards index
  4. The operator's logbook

Explanation

The model WHS Regulations prescribe the risk management obligations, including the requirement to work through the hierarchy of control to eliminate or minimise risks. Guidance material explains how to comply, but the legal force comes from the regulations. Manufacturer documents and logbooks are records, not sources of statutory duty.

Question 6Legislative and regulatory requirements, duty of care and standards

A crane operator is directed by a site supervisor to lift a load that exceeds the crane's rated capacity for the current configuration. What is the operator's most appropriate action?

  1. Ask the dogger to sign a waiver accepting the risk
  2. Complete the lift and record the overload in the logbook
  3. Perform the lift slowly under direct supervision
  4. Refuse the lift and explain the capacity limitation to the supervisor Correct answer.

Explanation

The operator has a duty not to operate plant outside its design limits and must not comply with a direction that would create an unacceptable risk. Refusing the lift and explaining the capacity limit is the correct response, and the matter should be escalated if pressed. No supervision level or paperwork can authorise an overload.

Question 7Legislative and regulatory requirements, duty of care and standards

Before starting a lift, a crane operator is handed a licence that appears altered. What is the most appropriate compliance action?

  1. Photocopy the licence and proceed with the lift
  2. Accept the licence because it shows a photograph
  3. Report it after the shift and continue working
  4. Verify the licence with the regulator and do not operate until confirmed Correct answer.

Explanation

Suspected false or altered licences must be verified directly with the issuing regulator before high risk work proceeds. Accepting a document at face value exposes the PCBU and the operator to serious legal risk. Verification is quick and should be done before any lift.

Question 8Legislative and regulatory requirements, duty of care and standards

A dogger holds a current basic rigging licence but is asked to direct a complex dual-crane lift. Which statement best reflects the licensing requirements?

  1. The lift can proceed if the load is under ten tonnes
  2. Any rigging licence authorises all lifting direction tasks
  3. The operator can authorise the dogger verbally
  4. The task requires competencies beyond the held class and must be reassessed before proceeding Correct answer.

Explanation

High risk work licences authorise only the classes and competencies listed on them, so a person must not perform tasks outside that scope. Complex lifts such as dual-crane operations require planning and appropriately competent personnel. The task should be reassessed and suitably licensed people assigned.

Question 9Legislative and regulatory requirements, duty of care and standards

What must a PCBU do when registering plant design or when plant is altered in a way that affects its structural integrity?

  1. Notify the insurer and take no further action
  2. Only update the maintenance schedule
  3. Continue operating while a retrospective note is filed
  4. Ensure the alteration is assessed and, where required, the design is re-registered Correct answer.

Explanation

Alterations that affect structural integrity or safe operation must be assessed by a competent person and, where the regulations require, the altered design must be registered before use. Uncontrolled modification can invalidate the original design registration and create serious risk. Documentation of the assessment must be retained.

Question 10Legislative and regulatory requirements, duty of care and standards

During a lift, a worker notices the crane's load moment indicator is showing a fault. Under the hierarchy of control, what should happen first?

  1. Ask the dogger to watch the indicator closely
  2. Increase the counterweight to compensate
  3. Stop the lift and eliminate the risk by taking the crane out of service Correct answer.
  4. Reduce the load by ten per cent and continue

Explanation

The hierarchy of control requires eliminating the hazard where reasonably practicable, which here means stopping work and removing the crane from service until the fault is rectified. Continuing with a faulty safety device relies on unverified assumptions. Engineering controls must be functional before operation resumes.

Question 11Legislative and regulatory requirements, duty of care and standards

A crane crew is preparing a lift near an overhead powerline. Which regulatory approach best reflects the required duty?

  1. Identify the hazard, consult the network operator and apply exclusion zones before work Correct answer.
  2. Proceed if the crane is insulated to a nominal rating
  3. Rely on the operator's judgement of safe clearance
  4. Ask the dogger to warn when the boom nears the line

Explanation

Working near overhead lines requires identifying the hazard, consulting the electricity network operator and establishing exclusion zones or de-energisation before work begins. These controls are prescribed because contact with live lines is potentially fatal. Human judgement and warning alone are not adequate controls.

Question 12Legislative and regulatory requirements, duty of care and standards

Which statement correctly describes the relationship between a high risk work licence and a statement of attainment?

  1. The statement of attainment is the legal authority to work
  2. Neither document is required if the operator has experience
  3. Both documents are interchangeable for compliance purposes
  4. The licence is the legal authority to work, while the statement of attainment records completed training Correct answer.

Explanation

The statement of attainment evidences that the required training and assessment were completed, but the high risk work licence issued by the regulator is the legal authority to perform the work. An unlicensed person must not operate even if they hold a statement of attainment. Employers should check both.

Question 13Legislative and regulatory requirements, duty of care and standards

A PCBU plans to use a crane for a lift that is not routine. What does the law require regarding a safe work method statement or lift study?

  1. A verbal briefing from the operator is sufficient
  2. Only the crane manufacturer needs to approve the lift
  3. A documented risk assessment and lift plan must be prepared and communicated before work Correct answer.
  4. The plan can be written after the lift is completed

Explanation

Non-routine or complex lifts require documented planning that identifies hazards, controls and responsibilities, and this must be communicated to the crew before work starts. The plan forms part of the PCBU's risk management duty. Preparing it afterwards defeats its purpose.

Question 14Legislative and regulatory requirements, duty of care and standards

An operator's licence is suspended by the regulator pending investigation. What is the operator's legal position regarding crane operation?

  1. The operator may continue if the employer gives written permission
  2. The operator may continue if supervised by a licensed person
  3. The operator may continue on private property only
  4. The operator must not perform licensed work until the suspension is lifted Correct answer.

Explanation

A suspended licence removes the legal authority to perform high risk work, and no employer permission or supervision arrangement can restore it. Operating during suspension is an offence and voids insurance cover. The operator must wait until the regulator reinstates the licence.

Question 15Legislative and regulatory requirements, duty of care and standards

A principal contractor wants to rely on a crane operator's licence as the sole control for a high risk lift. How should this be assessed under WHS law?

  1. Licensing is a minimum competency requirement, not a substitute for risk controls Correct answer.
  2. Licensing transfers the PCBU's duty to the operator
  3. Licensing is optional if the lift is short in duration
  4. Licensing fully discharges all duty holders' obligations

Explanation

A licence proves the holder has met a minimum competency standard, but duty holders must still identify hazards and apply controls such as planning, exclusion zones and inspection. Licensing does not transfer or extinguish the PCBU's duty of care. Short duration does not reduce the obligation.

Question 16Legislative and regulatory requirements, duty of care and standards

Two duty holders disagree about who must ensure a crane's annual inspection is current. How does WHS law allocate this responsibility?

  1. Each duty holder must discharge their own duty, and duties can overlap Correct answer.
  2. Only the site principal contractor is responsible
  3. Responsibility passes to whoever last used the crane
  4. Only the crane owner bears any responsibility

Explanation

WHS duties are concurrent, meaning more than one person can hold a duty for the same matter, and each must discharge their own duty to the extent they can influence the risk. Overlapping responsibility does not let one party assume another has covered it. Consultation and information sharing are required.

Question 17Hazard identification, risk assessment and control measures

Before a slewing mobile crane lifts a load near an overhead powerline, which control measure should be applied first?

  1. De-energise and isolate the line, or arrange an approved safety observer and exclusion zone Correct answer.
  2. Instruct the dogger to watch the wires during the lift
  3. Fit rubber sleeves to the hook block and slings
  4. Ask the crane operator to keep the boom well below the wires

Explanation

Eliminating the electrical hazard at its source is the highest-order control, so de-energising and isolating the line is preferred. Where isolation is not practicable, a documented exclusion zone combined with a safety observer is the recognised alternative. Insulation and vigilance do not remove the risk of arcing across the crane structure.

Question 18Hazard identification, risk assessment and control measures

What is the main purpose of a hazard identification and risk assessment before a lift?

  1. To identify foreseeable hazards and decide controls before work starts Correct answer.
  2. To calculate the hire charge for the crane
  3. To satisfy the client's paperwork requirements
  4. To record the crane's service history

Explanation

Risk assessment is a proactive process that finds hazards and puts controls in place before anyone is exposed. It should be done with the people doing the work and reviewed as conditions change. Its value lies in preventing incidents, not in producing documents.

Question 19Hazard identification, risk assessment and control measures

A crane is set up on compacted fill that has not been verified. Which hazard does this most directly create?

  1. Increased wind loading on the boom
  2. Shortened boom length
  3. Outrigger penetration or ground collapse under load Correct answer.
  4. Reduced hydraulic oil pressure

Explanation

Unverified fill can settle or fail under outrigger or track loading, causing the crane to tilt or overturn. Ground bearing capacity must be confirmed and suitable mats or pads used. Wind, hydraulics and boom geometry are separate issues.

Question 20Hazard identification, risk assessment and control measures

When should the lift study for a complex tandem lift be reviewed?

  1. Only if the client requests it
  2. Only after the lift is completed
  3. Before the lift and again whenever conditions or the plan change Correct answer.
  4. Once at the start of the project

Explanation

A lift study is a living document that must be reviewed before work begins and re-checked whenever anything affecting the lift changes. Changes in load, radius, ground, weather or personnel can invalidate the original controls. Reviewing only afterwards provides no protection.

Question 21Hazard identification, risk assessment and control measures

What does the hierarchy of control require a PCBU to do first when managing a crane hazard?

  1. Place warning signs around the hazard
  2. Train workers in safe behaviour
  3. Eliminate the hazard so far as is reasonably practicable Correct answer.
  4. Provide personal protective equipment

Explanation

The hierarchy ranks elimination highest because removing the hazard removes the risk entirely. Lower-order measures such as PPE, signage and training are used only when higher-order controls are not reasonably practicable. This ordering is central to WHS risk management.

Question 22Hazard identification, risk assessment and control measures

Which condition most increases the risk of a mobile crane overturning during a lift?

  1. Lifting a light load at a short radius
  2. Operating with the boom over the side on soft ground without mats Correct answer.
  3. Keeping the load close to the ground
  4. Using a rated capacity limiter that is functioning

Explanation

Side loading on soft ground without load-spreading mats concentrates pressure under the outriggers and can cause the crane to tip. Overturning risk rises with radius, load weight and poor ground bearing. Correct use of load-spreading and the rated capacity limiter reduces this risk.

Question 23Hazard identification, risk assessment and control measures

A load chart shows a capacity of 12 tonnes at the required radius, but the load is 9 tonnes and the rigging weighs 1.2 tonnes. What must the operator conclude?

  1. The lift exceeds capacity and must be replanned
  2. The lift is acceptable if the boom is kept short
  3. The lift is acceptable because the load alone is under capacity
  4. The combined load and rigging is within capacity at that radius Correct answer.

Explanation

Rated capacity must be compared with the total suspended load, which includes the rigging and any lifting attachments. Here 9 tonnes plus 1.2 tonnes equals 10.2 tonnes, which is below the 12 tonne rating. The operator must also confirm configuration and site conditions match the chart.

Question 24Hazard identification, risk assessment and control measures

During a lift the wind speed rises and the load has a large surface area. What is the most appropriate response?

  1. Increase hoist speed to finish before the wind strengthens
  2. Turn the crane so the load faces downwind
  3. Lower the load to a safe position and reassess against the crane's wind limits Correct answer.
  4. Continue the lift and monitor the load for swinging

Explanation

Large sail-area loads catch wind and increase side loading, which can overload the boom or cause loss of control. The operator should stop, land the load safely and reassess against the manufacturer's wind limits. Speed and orientation changes do not make the lift safer.

Question 25Hazard identification, risk assessment and control measures

A crane must slew a load over a public footpath adjacent to the site. Which control best manages the hazard to pedestrians?

  1. Schedule the lift for early morning when fewer people walk past
  2. Erect hoarding and close the footpath with a signed diversion during the lift Correct answer.
  3. Ask the dogger to shout warnings to pedestrians
  4. Rely on the crane's audible travel alarm

Explanation

Excluding people from the area beneath a suspended load is the most reliable control. Physical barriers and a signed diversion prevent pedestrians entering the drop zone. Warnings and alarms depend on people hearing and obeying them.

Question 26Hazard identification, risk assessment and control measures

What is the primary risk of lifting a load that has an unknown centre of gravity?

  1. The load may rotate or tilt unexpectedly once suspended Correct answer.
  2. The rated capacity limiter will switch off
  3. The boom will automatically retract
  4. The crane's fuel consumption will increase

Explanation

A load whose centre of gravity is not known can shift or rotate when lifted, causing loss of control and uneven sling loading. The load should be weighed or its balance point determined before rigging. Fuel, boom and limiter behaviour are unrelated to centre of gravity.

Question 27Hazard identification, risk assessment and control measures

Two cranes will lift a single load in tandem. Which factor is most critical to control?

  1. The number of spotters on site
  2. The load share between each crane as the load is moved Correct answer.
  3. The length of the crane's access track
  4. The colour coding of the slings

Explanation

In a tandem lift the load distribution between cranes changes as the load moves, and each crane must stay within its capacity at every stage. The lift plan must define the load share, the movement path and communications. Sling colour, spotter numbers and track length are secondary.

Question 28Hazard identification, risk assessment and control measures

A crane is working beside an excavation with a vertical cut face. What is the main concern for the lift plan?

  1. The crane may need a longer boom
  2. The load may become lighter
  3. The ground near the edge may collapse under outrigger loads Correct answer.
  4. The hook may swing less

Explanation

Outrigger loads close to an unsupported excavation edge can cause the face to fail, taking the crane with it. The crane must be set back a safe distance or the excavation supported, as determined by an engineer. Boom length and load weight are not the primary concern here.

Question 29Hazard identification, risk assessment and control measures

What should be done with a hazard that cannot be eliminated or substituted in a crane operation?

  1. Isolate people from it or apply engineering controls, then administrative controls and PPE Correct answer.
  2. Record it and proceed without further action
  3. Ignore it if the job is urgent
  4. Ask workers to sign a waiver

Explanation

When elimination and substitution are not possible, the hierarchy requires isolating people from the hazard or using engineering controls before administrative measures and PPE. Controls must be monitored to confirm they work. Ignoring or documenting a hazard without action leaves people exposed.

Question 30Hazard identification, risk assessment and control measures

Why must the area beneath a suspended load be treated as an exclusion zone?

  1. Because a dropped load or rigging failure can crush anyone underneath Correct answer.
  2. Because the operator cannot see through the load
  3. Because the crane's tyres may damage the surface
  4. Because the load may be too heavy for the crane

Explanation

Suspended loads can fall if rigging fails or the load shifts, and the area below is the drop zone. Keeping people out of that zone is the only reliable protection. Surface damage, capacity and visibility are separate considerations.

Question 31Hazard identification, risk assessment and control measures

A dogger notices the load beginning to drift sideways while suspended. What is the most appropriate immediate action?

  1. Grab the load and pull it back into line by hand
  2. Ask the operator to slew faster to correct the drift
  3. Signal the operator to stop and lower the load to a safe position Correct answer.
  4. Continue and adjust the load once it is at height

Explanation

Uncontrolled load movement signals a problem such as wind, snagging or an unbalanced load, so the load should be stopped and landed for reassessment. Manually restraining a drifting load exposes the dogger to crushing and struck-by hazards. Correcting at height increases the risk.

Question 32Hazard identification, risk assessment and control measures

Which document normally sets out the crane's rated capacities, boom configurations and permissible operating conditions?

  1. The crane hire agreement
  2. The delivery docket for the load
  3. The manufacturer's load chart for the specific crane Correct answer.
  4. The site induction booklet

Explanation

The manufacturer's load chart for the exact crane model and configuration gives the rated capacities and operating limits. It is the reference for planning every lift. Induction material, dockets and hire contracts do not contain capacity data.

Question 33Hazard identification, risk assessment and control measures

A lift plan specifies a two-leg sling at 60 degrees included angle, but the rigger uses a wider angle. What is the effect on leg tension?

  1. Leg tension is unchanged by the angle
  2. Leg tension depends only on the sling colour
  3. Leg tension decreases as the angle widens
  4. Leg tension increases as the included angle widens Correct answer.

Explanation

As the included angle between sling legs increases, each leg carries a greater share of the load and tension rises, reducing effective capacity. Rigs must follow the planned angle or the slings may be overloaded. Colour coding does not change the physics.

Question 34Hazard identification, risk assessment and control measures

A crane's rated capacity limiter alarms during a lift but the load is still moving. What does this indicate and what should happen?

  1. The limiter is faulty and should be bypassed
  2. The wind has dropped and the lift can continue
  3. The load is too light for the crane
  4. The crane is approaching or exceeding its rated capacity and the lift must stop Correct answer.

Explanation

A rated capacity limiter alarm means the crane is at or beyond its permitted load moment for the configuration. The lift must stop and be reassessed, for example by reducing radius, load or boom length. Bypassing the device removes a critical safety control.

Question 35Hazard identification, risk assessment and control measures

A crane will work on a slope. Which combination best controls the associated risks?

  1. Operate with one side's outriggers retracted to compensate
  2. Reduce the counterweight to lower the centre of gravity
  3. Use the boom to counter the slope
  4. Level the crane with outriggers on packed ground and verify the load chart for the configuration Correct answer.

Explanation

Cranes must be set up level, with outriggers fully extended on suitably prepared ground, and the load chart must match the actual configuration. Slopes alter load distribution and reduce stability if not corrected. Retracting outriggers, using the boom or altering counterweight compromises stability.

Question 36Hazard identification, risk assessment and control measures

During a lift near a live rail corridor, the crane's boom must pass over the tracks. Which control set best manages the risk?

  1. Fit flashing lights to the boom tip and proceed
  2. Coordinate with the rail authority for possession or isolation and define a verified exclusion zone Correct answer.
  3. Rely on the train drivers to slow down when they see the crane
  4. Complete the lift at night when fewer trains run

Explanation

Work over or near live rail infrastructure requires coordination with the rail authority, often a possession or isolation, plus a defined exclusion zone. Train operators cannot be relied on to react to a crane in time. Night work or lights do not remove the hazard.

Question 37Crane types, configurations, load charts and rated capacities

On a slewing mobile crane, what does the term 'rated capacity' represent?

  1. The load that causes the crane to reach its tipping point
  2. The load shown in the load chart for a specific configuration and radius, reduced for any applicable factors Correct answer.
  3. The mass of the load plus the hook block and all rigging
  4. The maximum load the crane can lift with the boom fully retracted and stationary

Explanation

Rated capacity is the value taken from the manufacturer's load chart for a particular boom length, radius and configuration, after any deductions or factors required by the chart notes are applied. It is not simply the tipping load, because structural limits and stability margins are built in.

Question 38Crane types, configurations, load charts and rated capacities

Which item must be subtracted from the gross load when checking a lift against the rated capacity?

  1. The outrigger pad mass
  2. The counterweight mass
  3. The mass of the operator's cabin
  4. The mass of the hook block and lifting attachments Correct answer.

Explanation

Gross load comprises the load plus hook block, slings, spreaders and any other lifting attachments below the boom head. All of these hang from the rope and therefore count against rated capacity. Counterweight and outrigger pads are part of the crane and are already accounted for in the chart.

Question 39Crane types, configurations, load charts and rated capacities

A load chart column is headed 'radius'. From which point is radius normally measured on a slewing mobile crane?

  1. The tip of the boom, measured along the boom
  2. The nearest outrigger pad, measured to the load edge
  3. The centre of slew rotation, measured horizontally to the centre of the load Correct answer.
  4. The rear of the crane chassis, measured to the hook

Explanation

Radius is the horizontal distance from the crane's centre of rotation to the centre of gravity of the suspended load. Measuring to the near edge or along the boom gives a shorter, unsafe figure.

Question 40Crane types, configurations, load charts and rated capacities

Why does rated capacity decrease as radius increases on a slewing mobile crane?

  1. Because hydraulic pressure falls at longer reach
  2. Because the hook block becomes heavier
  3. Because the overturning moment and boom stresses increase with radius Correct answer.
  4. Because the wire rope diameter changes with boom extension

Explanation

As radius grows, the same load creates a larger overturning moment and greater bending stress in the boom. Both stability and structural limits therefore reduce the permissible load.

Question 41Crane types, configurations, load charts and rated capacities

What is the purpose of the 'boom length' dimension in a load chart?

  1. It identifies which capacity column applies for the configuration being used Correct answer.
  2. It sets the required counterweight
  3. It determines the maximum hook height only
  4. It fixes the maximum permissible wind speed

Explanation

Load charts are tabulated by boom length as well as radius, because a longer boom weighs more and has different structural limits. The operator must use the column matching the actual boom length in use.

Question 42Crane types, configurations, load charts and rated capacities

What does 'configuration' mean when selecting a load chart for a slewing mobile crane?

  1. The site traffic management plan
  2. The colour scheme of the crane
  3. The operator's shift roster
  4. The combination of boom type, counterweight, outrigger setup and attachments in use Correct answer.

Explanation

Configuration covers the physical setup of the crane, such as boom or jib type, counterweight state, outrigger beam extension and any fly jib fitted. Each combination has its own chart or chart section.

Question 43Crane types, configurations, load charts and rated capacities

A crane is set up on outriggers with beams fully extended. Which chart section applies?

  1. Any chart, provided the load is under 50 percent
  2. The chart for crawler operation
  3. The chart for the outrigger configuration actually deployed Correct answer.
  4. The chart for free-on-wheels operation

Explanation

The chart section matching the deployed outrigger configuration must be used, because beam extension and pad position change the stability base. Using a chart for a different configuration invalidates the capacity figures.

Question 44Crane types, configurations, load charts and rated capacities

Where should the load chart used by the operator come from?

  1. The manufacturer's chart for that specific crane model and configuration Correct answer.
  2. A generic chart for the crane's tonnage class
  3. A chart prepared by the rigging crew
  4. A chart copied from a similar crane on site

Explanation

Only the manufacturer's chart for the specific model and configuration is valid, because capacities reflect that machine's structural and stability design. Generic or borrowed charts can overstate capacity.

Question 45Crane types, configurations, load charts and rated capacities

A crane has a rated capacity of 12.0 t at the working radius. The load mass is 10.2 t, the hook block is 0.6 t and slings are 0.2 t. What is the percentage of rated capacity used?

  1. 92 percent Correct answer.
  2. 85 percent
  3. 95 percent
  4. 88 percent

Explanation

Gross load is 10.2 + 0.6 + 0.2 = 11.0 t. Dividing 11.0 by 12.0 gives approximately 0.917, or about 92 percent of rated capacity.

Question 46Crane types, configurations, load charts and rated capacities

The chart shows 8.5 t at 14 m radius and 7.2 t at 16 m radius. The actual radius is 15 m. Which capacity should be used?

  1. The average, 7.85 t
  2. Either figure, because 15 m lies between them
  3. 7.2 t, the lower of the two figures Correct answer.
  4. 8.5 t, the higher of the two figures

Explanation

When the actual radius falls between charted radii, the operator must use the capacity for the next longer radius, which is the lower value. Interpolating or averaging is not permitted unless the manufacturer specifically provides for it.

Question 47Crane types, configurations, load charts and rated capacities

A crane is rated 20 t at 10 m radius in the outrigger chart. The load is 15 t and the radius is measured as 10 m. What additional check is most important before lifting?

  1. Confirming ground bearing pressure under each outrigger is adequate Correct answer.
  2. Confirming the wind is below 25 m/s
  3. Confirming the hook is fully lowered
  4. Confirming the boom angle is below 45 degrees

Explanation

Even when the chart capacity is satisfied, the outrigger loads must be supported by ground capable of carrying them. Ground bearing failure can cause overturning regardless of chart compliance.

Question 48Crane types, configurations, load charts and rated capacities

What does a load chart note stating 'capacities above the heavy line are limited by structural strength' mean?

  1. The line marks the maximum permissible wind speed
  2. The chart region above the line is governed by boom or component strength rather than tipping Correct answer.
  3. The crane cannot be operated above the line
  4. Loads above the line must be lifted more slowly

Explanation

Charts often distinguish regions limited by structural capacity from those limited by stability. Above the heavy line, the binding limit is the strength of the boom or other components, so the crane may tip before reaching that load only in the stability region.

Question 49Crane types, configurations, load charts and rated capacities

A crane is configured with a fly jib. How should the load chart be applied?

  1. Use the main boom chart and deduct the jib mass
  2. Use the chart for the next larger crane model
  3. Use the dedicated fly jib chart or chart section Correct answer.
  4. Use the main boom chart and add 10 percent

Explanation

Fitting a fly jib changes the boom mass, geometry and structural limits, so a dedicated chart or chart section applies. The main boom chart does not reflect the jib configuration.

Question 50Crane types, configurations, load charts and rated capacities

Which factor is included in the gross load but not in the net load?

  1. The counterweight
  2. The outrigger floats
  3. The hook block and slings Correct answer.
  4. The payload being lifted

Explanation

Net load is the payload itself, while gross load adds the hook block, slings and any other suspended attachments. Charts are generally expressed in terms of gross load, so the difference matters when comparing to rated capacity.