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MT Crane/Hoisting Operator practice questions

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Question 1Crane Types, Components, and Terminology

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

  1. The maximum load the crane can lift with the boom fully retracted, ignoring configuration
  2. The total weight of the crane including counterweight and outrigger floats
  3. The breaking strength of the hoist rope divided by a design factor
  4. The load the crane may lift in a specific configuration after deductions for hook block and rigging Correct answer.

Explanation

Rated capacity is the load value read from the manufacturer's chart for a specific boom length, radius, and quadrant, after subtracting the weight of the hook block, slings, and other lifting attachments. Gross capacity minus these deductions gives the net load that may be lifted.

Question 2Crane Types, Components, and Terminology

What is the primary purpose of a lattice boom on a crawler crane compared with a hydraulic telescopic boom?

  1. To provide high strength at low weight for long reach and high capacity at larger radii Correct answer.
  2. To allow the boom to be extended and retracted under load with hydraulic cylinders
  3. To permit operation without any counterweight or superstructure
  4. To eliminate the need for a load moment indicator

Explanation

A lattice boom is a truss structure that gives a high strength-to-weight ratio, allowing long boom and jib combinations and good capacity at long radius. Telescopic booms are quicker to set up but are generally heavier per unit length and limited in length.

Question 3Crane Types, Components, and Terminology

In crane terminology, what is 'radius' measured to?

  1. The center of rotation of the crane to the center of the hook or load line, measured horizontally Correct answer.
  2. The outrigger pad to the nearest obstruction
  3. The boom pivot pin to the boom tip, measured along the boom
  4. The ground level to the underside of the boom tip

Explanation

Radius is the horizontal distance from the crane's center of rotation to the center of the hook or load line, with the boom at the working angle. It is the value used to enter the load chart, so measuring it to the wrong point gives an unsafe capacity.

Question 4Crane Types, Components, and Terminology

A crane has a 12 t hook block reeved with 4 parts of line. Which statement about the hoist line pull is correct?

  1. Line pull equals the load divided by the number of parts of line, ignoring friction and rope weight Correct answer.
  2. Line pull equals the load multiplied by the number of parts of line
  3. Line pull equals the load divided by the number of sheaves in the boom tip only
  4. Line pull is independent of the number of parts of line

Explanation

With a multi-part reeving, the load is shared among the parts of line, so the pull in a single line is approximately the load divided by the number of parts, before friction losses are added. More parts of line therefore reduce line pull and increase the load the hoist can handle.

Question 5Crane Types, Components, and Terminology

What is the function of a load moment indicator (LMI) on a mobile crane?

  1. To record engine hours for maintenance scheduling
  2. To measure wind speed at the boom tip and stop the hoist
  3. To compare actual load and radius against the rated capacity and warn or cut out before overload Correct answer.
  4. To lock the swing brake when the boom exceeds a set angle

Explanation

The LMI senses boom angle, length, and load to calculate the moment being imposed and compares it with the programmed load chart. It gives a warning as capacity is approached and, at the limit, prevents movements that would increase the overload.

Question 6Crane Types, Components, and Terminology

Which component transfers the crane's load from the superstructure to the ground through the carrier when outriggers are used?

  1. The hoist drum and brake
  2. The swing bearing and the outrigger beams with their floats or pads Correct answer.
  3. The boom head sheaves
  4. The counterweight bolts

Explanation

The swing bearing carries the superstructure loads into the carrier frame, and the outrigger beams with their floats spread that load into the ground. Ground bearing pressure under the floats is what determines whether the crane stays level and stable.

Question 7Crane Types, Components, and Terminology

What does 'boom angle' mean on a crane with a luffing boom?

  1. The angle between the boom and the horizontal, measured at the boom pivot Correct answer.
  2. The angle of the outrigger beam to the carrier
  3. The angle of the hook block to the vertical
  4. The angle between the two sides of the lattice boom

Explanation

Boom angle is the angle of the boom centerline above the horizontal, taken at the boom foot or pivot. Together with boom length it fixes the radius, which is why angle indicators and the LMI rely on it.

Question 8Crane Types, Components, and Terminology

A crane is rated 20 t at 10 m radius and 14 t at 14 m radius. If the load is moved out from 10 m to 14 m, what happens to the allowable load if all other factors are unchanged?

  1. It is unaffected until the LMI alarm sounds
  2. It stays the same because the load itself has not changed
  3. It increases because the boom is lower
  4. It decreases to the value charted for the new, larger radius Correct answer.

Explanation

Capacity falls as radius increases because the overturning moment from the load grows with the distance from the center of rotation. The chart value for the new radius must be used, and if the load exceeds it the operation is an overload.

Question 9Crane Types, Components, and Terminology

What is the role of the counterweight on a crane superstructure?

  1. To replace the outriggers when working on firm ground
  2. To increase lifting capacity by adding weight to the load line
  3. To act as ballast that must be removed before lifting near capacity
  4. To provide a moment opposing the load moment and so improve stability and capacity Correct answer.

Explanation

Counterweight sits behind the center of rotation and creates a moment that offsets part of the load moment, improving stability and charted capacity. It does not add to lifting capacity through the rope and must never be treated as part of the load.

Question 10Crane Types, Components, and Terminology

Which term describes the crane configuration where the boom is fitted with an auxiliary jib to gain extra height or reach?

  1. Free-fall configuration
  2. Jib configuration Correct answer.
  3. Boom dolly configuration
  4. Superlift configuration

Explanation

A jib is an auxiliary boom section mounted at the boom tip to increase height or offset reach at reduced capacity. The load chart for the jib configuration must be used, since capacity is lower than for the main boom alone.

Question 11Crane Types, Components, and Terminology

What is 'ground bearing pressure' in relation to crane setup?

  1. The pressure in the hoist circuit when lifting at maximum radius
  2. The pressure inside the hydraulic outrigger cylinder
  3. The pressure the crane's outrigger float imposes on the supporting surface Correct answer.
  4. The pressure of the wind on the boom surface

Explanation

Ground bearing pressure is the load per unit area transmitted through the outrigger float or track into the ground. It must be compared with the ground's capacity, using mats or cribbing where necessary, or the crane may settle and tip.

Question 12Crane Types, Components, and Terminology

Which device is fitted to prevent the hook block from being pulled into the boom tip?

  1. The anti-two-block device Correct answer.
  2. The hoist brake
  3. The boom luffing cylinder
  4. The swing lock

Explanation

The anti-two-block device senses when the hook block approaches the boom tip and stops the hoisting and booming-down functions before contact occurs. Contact can part the rope and drop the load, so the device must be tested during setup.

Question 13Crane Types, Components, and Terminology

A crane is set up on a slope. Why is leveling the carrier before lifting critical?

  1. It removes the need for outrigger floats on soft ground
  2. It allows the boom to be extended further than the chart permits
  3. It keeps the load chart valid, since charts assume the crane is level within the manufacturer's tolerance Correct answer.
  4. It reduces the fuel consumption of the carrier engine

Explanation

Load charts are calculated for a level machine, and tilting shifts the load and boom geometry, changing radius and side loading on the boom. Working out of level can therefore overload the crane even at a radius that looks acceptable.

Question 14Crane Types, Components, and Terminology

What does the term 'parts of line' refer to on a crane?

  1. The number of rope falls running between the boom tip sheaves and the hook block Correct answer.
  2. The number of load chart lines applicable to the configuration
  3. The number of boom sections in the telescopic boom
  4. The number of outrigger beams deployed

Explanation

Parts of line is the count of rope falls supporting the hook block, determined by how the rope is reeved through the tip and block sheaves. It sets the line pull and the maximum load the reeving can handle.

Question 15Crane Types, Components, and Terminology

Which statement best describes a crawler crane's lifting capability compared with a wheeled mobile crane of similar capacity?

  1. It cannot travel with a load suspended under any circumstances
  2. It can lift on its tracks without outriggers, spreading load over a larger area Correct answer.
  3. It must always deploy outriggers before any lift
  4. It has a higher road speed and so is preferred for highway work

Explanation

A crawler crane carries its load on track shoes, which spread the weight over a large ground area and allow lifting and travel without outriggers. This suits site work on prepared ground but makes road travel impractical without a transporter.

Question 16Crane Types, Components, and Terminology

On a load chart, what does the shaded or blocked area typically indicate?

  1. Regions where only the auxiliary hoist may be used
  2. Areas where the load chart has been superseded by a newer edition
  3. Radii where the crane may operate at full capacity
  4. Zones or configurations where lifting is not permitted, such as over the side without full outrigger deployment Correct answer.

Explanation

Chart areas that are shaded or struck through mark configurations the manufacturer does not rate, for example lifting over the side or rear with outriggers retracted. Operating in those zones is outside the charted capacity and is not permitted.

Question 17Crane Types, Components, and Terminology

What is the purpose of the swing brake or swing lock on a crane?

  1. To lock the outrigger beams in the extended position
  2. To hold the hook block at a set height
  3. To hold the superstructure from rotating when the crane is parked or when rotation must be controlled Correct answer.
  4. To stop the boom from lowering under load

Explanation

The swing brake and swing lock act on the slewing system to prevent or control rotation of the superstructure. They are used when parking the machine and when rotation must be restrained, but they are not a substitute for controlling a swinging load.

Question 18Crane Types, Components, and Terminology

Which of these best defines 'boom length' as used to enter a load chart?

  1. The distance from the boom pivot to the boom tip along the boom Correct answer.
  2. The height of the boom tip above the ground
  3. The distance from the boom pivot to the counterweight
  4. The horizontal distance from the crane center to the boom tip

Explanation

Boom length is measured along the boom from the foot or pivot pin to the tip, and it is one of the two values, with radius or angle, needed to read a chart. It is not a horizontal or vertical distance.

Question 19Crane Types, Components, and Terminology

Why must the weight of the hook block and slings be deducted from the gross chart capacity?

  1. Because they are part of the load the crane is actually supporting and count against capacity Correct answer.
  2. Because they are excluded from the load moment calculation
  3. Because they change the boom angle during the lift
  4. Because they reduce the strength of the hoist rope

Explanation

Everything hanging below the boom tip is supported by the crane, so the hook block, slings, and any spreader beams use up part of the charted capacity. Deducting their weight gives the net capacity available for the actual load.

Question 20Crane Types, Components, and Terminology

What is a 'flying jib' on a lattice boom crane?

  1. A rope guide fitted to the hoist drum
  2. A hydraulic cylinder that raises the boom
  3. A counterweight section that swings out during lifting
  4. A jib that is stowed on the boom and can be pinned in place by the operator without full reassembly Correct answer.

Explanation

A flying jib is carried on the boom and can be swung or pinned into its working position without stripping the boom, saving setup time. Its use still requires the jib configuration chart, which gives lower capacity than the main boom.

Question 21Crane Types, Components, and Terminology

Which statement correctly describes the difference between gross and net load on a crane?

  1. Gross and net load are the same value on all cranes
  2. Gross load includes the payload plus rigging and hook block; net load is the payload alone Correct answer.
  3. Net load is always larger than gross load
  4. Gross load is the payload only; net load includes rigging

Explanation

Gross load is everything the crane supports, including the hook block, slings, and payload, while net load is the useful payload remaining after deductions. Confusing the two is a common cause of overloading at long radius.

Question 22Crane Types, Components, and Terminology

A crane chart gives 8 t capacity at a given radius; the hook block weighs 0.5 t and slings weigh 0.2 t. What is the maximum payload?

  1. 8.0 t
  2. 8.7 t
  3. 7.3 t Correct answer.
  4. 7.5 t

Explanation

The rigging and hook block are supported by the crane, so both are deducted from the charted capacity: 8.0 minus 0.5 minus 0.2 equals 7.3 t of payload. Using the full 8 t would overload the crane by the weight of the attachments.

Question 23Crane Types, Components, and Terminology

What does 'boom deflection' mean and why does it matter?

  1. The settling of the outrigger pads into the ground
  2. The rotation of the superstructure during slewing
  3. The stretch of the hoist rope under load
  4. The sideways or downward bend of the boom under load, which increases radius and reduces capacity Correct answer.

Explanation

Under load the boom bends, so the actual radius is greater than the geometric radius with the boom unloaded. This increases the load moment, which is why charts are built with deflection allowance and why some charts require the loaded radius to be checked.

Question 24Crane Types, Components, and Terminology

Which item is part of the crane's 'superstructure' rather than the carrier?

  1. The boom and its pivot, mounted on the rotating upper works Correct answer.
  2. The outrigger beams
  3. The carrier frame and axles
  4. The outrigger floats

Explanation

The superstructure is the rotating upper works: boom, hoist, cab, and counterweight, mounted on the swing bearing. The carrier provides the chassis, axles, and outriggers that support the superstructure.

Question 25Load Charts, Capacity, and Rated Load Determination

On a lattice-boom crawler crane load chart, the capacity listed for a given radius already includes which of the following deductions?

  1. The weight of the hook block and all lifting attachments Correct answer.
  2. The weight of the boom and jib
  3. The weight of the operator and fuel
  4. The weight of the crane's counterweight

Explanation

Rated capacities in the chart are net values: the published figure is the load that may be lifted after the hook block, slings, and other lifting gear below the boom tip are subtracted. The boom, jib, counterweight, and machine masses are already built into the chart as the crane's own configuration. Confusing gross and net capacity is a leading cause of overload.

Question 26Load Charts, Capacity, and Rated Load Determination

A crane's load chart shows 12,000 lb at a 20 ft radius and 9,500 lb at a 25 ft radius. The load will be set at a measured radius of 22 ft. Which capacity should the operator use?

  1. The value for the next longer radius on the chart, 9,500 lb Correct answer.
  2. The average of the two listed values, 10,750 lb
  3. 12,000 lb, because the load is closer than 25 ft
  4. 9,500 lb only if the boom is fully retracted

Explanation

When the actual radius falls between two chart values, the operator must use the capacity for the next longer (larger) radius, because capacity decreases as radius increases. Interpolating upward or averaging would assume a capacity the chart does not guarantee. The conservative next-longer-radius value is 9,500 lb.

Question 27Load Charts, Capacity, and Rated Load Determination

What does the term 'rated capacity' mean on a manufacturer's load chart?

  1. The load the crane is designed to lift under the chart's specified conditions Correct answer.
  2. The load at which the hydraulic system relieves
  3. The maximum load the crane can lift with the boom at minimum radius
  4. The load that causes the crane to tip

Explanation

Rated capacity is the load the manufacturer states the crane may lift under the specific conditions of the chart (configuration, radius, boom length, and any notes). It already incorporates the required margin against tipping and structural failure. It is not the tipping load or a hydraulic limit.

Question 28Load Charts, Capacity, and Rated Load Determination

A load chart has separate columns for 'over the front' and 'over the side.' What is the main reason these capacities differ?

  1. The boom is stronger when facing forward
  2. The outriggers are longer at the front
  3. The operator has better visibility over the front
  4. Structural strength and stability vary with the direction of the load relative to the crane's chassis Correct answer.

Explanation

Crane strength and stability depend on which part of the chassis and which outrigger or crawler footprint carries the load. Manufacturers publish separate ratings for each working area because the tipping axis and structural limits change with direction. Visibility and boom strength do not vary in the way the other options imply.

Question 29Load Charts, Capacity, and Rated Load Determination

An operator must pick a load whose weight is known to be 8,000 lb. The chart at the planned radius shows 8,400 lb for the main hook and 6,900 lb for the auxiliary (whip) hook. What is the correct action?

  1. Use the main hook, since 8,000 lb is within 8,400 lb Correct answer.
  2. Use either hook because both are below the load weight
  3. Use the auxiliary hook because it is lighter
  4. Reduce the radius until the auxiliary hook capacity exceeds 8,000 lb

Explanation

The main hook's rating at the planned radius (8,400 lb) exceeds the 8,000 lb load, so that configuration is acceptable. The auxiliary hook rating of 6,900 lb is below the load, so it cannot be used at that radius. The hook's own weight is already part of the net capacity.

Question 30Load Charts, Capacity, and Rated Load Determination

What is the purpose of the notes printed on a crane load chart?

  1. To record the operator's daily inspection
  2. To list the crane's maintenance schedule
  3. To give the crane's purchase price and options
  4. To specify conditions and limits that the capacities depend on Correct answer.

Explanation

The chart notes define the conditions under which the capacities are valid, such as outrigger extension, ground bearing, boom configuration, and wind limits. A capacity is only rated if those conditions are met. Ignoring the notes can invalidate the chart value entirely.

Question 31Load Charts, Capacity, and Rated Load Determination

A crane is lifting on rubber (without outriggers) and the chart shows 5,000 lb for stationary pick-and-carry and 3,200 lb for pick-and-carry travel. The load is 4,000 lb and the crane must travel with it. Which rating governs?

  1. The sum of the two values
  2. The higher of the two values
  3. 3,200 lb, because the load will be carried while travelling Correct answer.
  4. 5,000 lb, because the crane is stationary while lifting

Explanation

When the operation involves travelling with the load, the pick-and-carry travel rating governs, and here 3,200 lb is below the 4,000 lb load, so the lift is not permitted as planned. The stationary rating applies only when the crane does not travel with the load. The operator must reduce the load or change the plan.

Question 32Load Charts, Capacity, and Rated Load Determination

Which document ultimately governs the capacity an operator may use for a specific lift?

  1. The manufacturer's load chart for the crane's exact configuration Correct answer.
  2. The rigging plan prepared by the customer
  3. The previous operator's notes
  4. The crane's rated capacity indicator alarm setting

Explanation

The manufacturer's load chart for the exact configuration (boom length, radius, counterweight, outrigger or crawler setup) is the governing document. The rated capacity indicator is a warning device and does not replace the chart. Plans and notes from others do not override the chart.

Question 33Load Charts, Capacity, and Rated Load Determination

A load chart lists capacity for a 60 ft boom at 30 ft radius as 10,200 lb. The crane is rigged with a 60 ft boom plus a 25 ft jib offset at 15 degrees. How should the operator determine capacity?

  1. Use the main boom value and subtract the jib's weight only
  2. Use the 10,200 lb main boom value directly
  3. Use the jib chart or jib deduction specified for that configuration Correct answer.
  4. Add the jib length to the boom length and read the main chart

Explanation

A jib changes the crane's geometry and load path, so the manufacturer publishes separate jib ratings or a jib deduction that must be applied. The main boom value alone does not apply once a jib is fitted and offset. The operator must consult the jib-specific chart or note.

Question 34Load Charts, Capacity, and Rated Load Determination

A crane chart gives 14,000 lb at a 16 ft radius. The load weighs 11,500 lb, the hook block weighs 900 lb, and the slings weigh 400 lb. What is the total load against the chart?

  1. 12,400 lb
  2. 12,800 lb Correct answer.
  3. 14,000 lb
  4. 11,500 lb

Explanation

The load on the chart is the sum of the payload, hook block, and rigging: 11,500 + 900 + 400 = 12,800 lb. That total must be compared with the 14,000 lb rating, leaving only 1,200 lb of margin. Deducting only the payload would overstate the available margin.

Question 35Load Charts, Capacity, and Rated Load Determination

The load chart shows 18,000 lb at 12 ft radius and 15,500 lb at 15 ft radius. The measured radius is 13.5 ft. Which capacity applies?

  1. 18,000 lb
  2. 15,500 lb Correct answer.
  3. 15,500 lb only if the boom length matches
  4. 16,750 lb (interpolated)

Explanation

Because 13.5 ft lies between two charted radii, the operator must use the capacity for the next longer radius, 15,500 lb. Interpolating produces a value the chart does not certify. The conservative next-longer-radius rule protects against small radius measurement errors.

Question 36Load Charts, Capacity, and Rated Load Determination

A crane is rated 20,000 lb at 15 ft radius with outriggers fully extended. The outriggers can only be extended to the mid-position, which the chart lists separately at 16,500 lb for the same radius. What capacity applies?

  1. 20,000 lb, because the radius is unchanged
  2. 20,000 lb, provided the ground is level
  3. The average of the two values
  4. 16,500 lb, because the chart for the actual outrigger position governs Correct answer.

Explanation

Capacity depends on outrigger extension because it changes the tipping axis and structural support. When the outriggers are not fully extended, the chart for that specific position governs. Level ground does not restore capacity lost through reduced outrigger spread.

Question 37Load Charts, Capacity, and Rated Load Determination

A load chart includes a footnote: 'Capacities above the bold line are based on structural strength; capacities below the bold line are based on stability.' A lift falls below the bold line. What does this mean for the operator?

  1. The boom may fail structurally before the crane tips
  2. Hydraulic pressure is the limiting factor
  3. The crane will tip before the boom fails structurally Correct answer.
  4. The load is safe regardless of ground conditions

Explanation

Below the bold line, stability governs, meaning the crane would tip before reaching its structural limit. This makes ground bearing, leveling, and outrigger setup especially critical. Above the line, structural strength governs instead.

Question 38Load Charts, Capacity, and Rated Load Determination

A crane chart gives 9,000 lb at 40 ft radius for a 90 ft boom. The operator must lift a 9,000 lb load, and the hook block and rigging weigh 700 lb. What is the correct conclusion?

  1. The lift is acceptable if the boom is shortened
  2. The lift is acceptable because the load equals the rating
  3. The lift is acceptable if the wind is calm
  4. The lift is not acceptable because the total load exceeds the rating Correct answer.

Explanation

The total load against the chart is 9,000 lb plus 700 lb of hook block and rigging, or 9,700 lb, which exceeds the 9,000 lb rating. The payload alone equalling the rating is not sufficient because rigging must be added. The operator must reduce the load or increase capacity by changing configuration.

Question 39Load Charts, Capacity, and Rated Load Determination

What is the effect on rated capacity when the boom length is increased while radius is held constant?

  1. Capacity generally decreases because the longer boom adds weight and reduces structural margin Correct answer.
  2. Capacity doubles when boom length doubles
  3. Capacity generally increases because the boom reaches higher
  4. Capacity is unchanged because radius is unchanged

Explanation

A longer boom adds its own weight and reduces the structural margin at the boom tip, so capacity at a given radius generally decreases. Radius alone does not determine capacity; boom length is a separate chart variable. The relationship is not proportional.

Question 40Load Charts, Capacity, and Rated Load Determination

A crane is set up on a slope, and the chart note requires the crane to be level within 1 percent. The operator cannot confirm level. What is the correct action?

  1. Proceed and reduce capacity by 10 percent
  2. Proceed if outriggers are fully extended
  3. Level the crane or do not lift, because the chart assumes a level machine Correct answer.
  4. Proceed if the load is well below the charted capacity

Explanation

Charted capacities assume the machine is level within the stated tolerance; an out-of-level crane shifts the load and can tip at a lower radius than charted. The operator must level the crane before lifting. Reducing capacity by an arbitrary percentage does not restore the chart's validity.

Question 41Load Charts, Capacity, and Rated Load Determination

A load chart has a column headed 'boom angle' and another headed 'radius.' Why must the operator use radius rather than boom angle to read capacity?

  1. Boom angle changes with load weight
  2. Radius is the horizontal distance from the rotation center to the load and directly determines the tipping moment Correct answer.
  3. Radius is fixed regardless of boom position
  4. Boom angle is easier to measure accurately

Explanation

Capacity is governed by the horizontal distance from the crane's rotation center to the load, which is the radius and directly sets the tipping moment. Boom angle is an indicator but does not by itself capture that distance. Using angle alone can misstate the true radius.

Question 42Load Charts, Capacity, and Rated Load Determination

A crane's chart lists 11,000 lb at 25 ft radius. The load is 10,500 lb, and the operator plans to swing the load over a side where the chart lists 9,800 lb at the same radius. What must the operator do?

  1. Reduce the load or radius so it is within the 9,800 lb side rating Correct answer.
  2. Proceed, because the load is within the 11,000 lb rating
  3. Proceed if the swing is slow
  4. Proceed if the outriggers are fully extended

Explanation

The capacity that governs is the one for the working area the load will actually pass over. Since the side rating is 9,800 lb and the load is 10,500 lb, the lift exceeds capacity in that area. The operator must reduce the load or radius, or avoid that side.

Question 43Load Charts, Capacity, and Rated Load Determination

What does the term 'gross capacity' most commonly refer to in some load charts?

  1. The capacity with the boom at minimum radius
  2. The capacity after deducting all rigging
  3. The capacity before deducting the weight of the hook block and rigging Correct answer.
  4. The tipping load of the crane

Explanation

Some charts publish gross capacity, which is the total load the crane can support before the hook block and rigging are deducted. The operator must then subtract those items to find the usable payload. Confusing gross and net capacity can lead to overloading.

Question 44Load Charts, Capacity, and Rated Load Determination

A crane chart shows 7,500 lb at 50 ft radius for a 110 ft boom. The operator plans to lift 7,200 lb but must also account for a 500 lb hook block and 300 lb of slings. What is the correct assessment?

  1. Acceptable, because the hook block is part of the crane
  2. Acceptable, because 7,200 lb is below 7,500 lb
  3. Not acceptable, because total load is 8,000 lb, above the rating Correct answer.
  4. Not acceptable only if wind exceeds 20 mph

Explanation

The total load is 7,200 + 500 + 300 = 8,000 lb, which exceeds the 7,500 lb rating. The hook block and slings must be counted against the chart. The operator must reduce the load or change configuration to increase capacity.

Question 45Load Charts, Capacity, and Rated Load Determination

A crane is required to lift over a wall, and the chart note states that capacities apply only when the load is within the boom's rated working area. The load will pass outside that area. What is the correct action?

  1. Proceed if a signal person is used
  2. Proceed if the load is under half the charted capacity
  3. Proceed at reduced speed
  4. Do not lift outside the rated working area; the chart does not cover that condition Correct answer.

Explanation

Charted capacities are valid only within the working areas the manufacturer specifies. Lifting outside those areas is outside the chart's coverage and requires different engineering, not a speed or margin adjustment. The operator must stop and obtain a proper plan.

Question 46Load Charts, Capacity, and Rated Load Determination

A load chart gives 6,000 lb at 60 ft radius. The operator measures radius with the boom at the load's centerline, but the load's center of gravity is offset 4 ft from the hook because of an unbalanced load. How should radius be treated?

  1. Use the measured 60 ft radius regardless of load offset
  2. Increase the effective radius to account for the load's offset center of gravity Correct answer.
  3. Decrease the radius because the load hangs lower
  4. Use the boom angle instead of radius

Explanation

An offset center of gravity shifts the effective load point outward, increasing the true radius and the tipping moment beyond the measured hook position. The operator must account for that offset, which reduces capacity. Ignoring it can overload the crane even when the hook radius looks acceptable.

Question 47Load Charts, Capacity, and Rated Load Determination

A crane chart shows 22,000 lb at 10 ft radius and 19,000 lb at 12 ft radius. The operator's measured radius is 11.2 ft, but the measurement has an uncertainty of plus or minus 0.5 ft. Which capacity should govern?

  1. 19,000 lb, because the upper bound of the radius falls in the 12 ft range Correct answer.
  2. 22,000 lb, because the nominal radius is closer to 10 ft
  3. 20,500 lb, interpolated between the two values
  4. 22,000 lb, because the uncertainty is small

Explanation

With uncertainty, the operator must consider the maximum credible radius, which is 11.7 ft and falls in the 12 ft range, so the 19,000 lb value governs. Using the nominal radius or interpolating ignores the measurement uncertainty. Conservative selection protects against tipping.

Question 48Load Charts, Capacity, and Rated Load Determination

A crane's chart lists capacity for a given radius on outriggers and on rubber. The job requires the crane to be positioned partly over a basement wall, where the ground cannot be verified to carry the outrigger load. What is the controlling consideration?

  1. The outrigger capacity, because outriggers are always stronger
  2. The on-rubber capacity, because ground bearing under outriggers cannot be assured Correct answer.
  3. The higher of the two capacities
  4. The capacity at minimum radius

Explanation

Outrigger capacity depends on the ground or structure beneath each float carrying the load. Where bearing cannot be verified, the outrigger rating is not valid, and the lower on-rubber rating or a different setup must govern. Choosing the higher number without verified support risks a collapse.

Question 49Load Charts, Capacity, and Rated Load Determination

A load chart's capacity at a given radius is 15,000 lb, but a note states that capacities must be reduced by 20 percent when the boom is fitted with a certain attachment. The load is 13,000 lb. What is the correct conclusion?

  1. Not acceptable, because the reduced capacity is 12,000 lb, below the load Correct answer.
  2. Acceptable, because 13,000 lb is below 15,000 lb
  3. Acceptable if the load is lifted slowly
  4. Acceptable, because the reduction applies only above 15,000 lb

Explanation

The note reduces the charted capacity by 20 percent, giving 12,000 lb, which is below the 13,000 lb load. The note is part of the chart and must be applied before comparing the load. Lifting slowly does not restore capacity.

Question 50Load Charts, Capacity, and Rated Load Determination

A load chart column is headed 'radius (ft)' and the values run from 10 to 60. What does the radius value represent for a crane in the lifting configuration?

  1. The arc length traveled by the boom tip between the stowed and working positions
  2. The vertical height of the boom tip above the ground at the given boom angle
  3. The straight-line distance from the boom pivot pin to the center of the hook block
  4. The horizontal distance from the crane's center of rotation to the vertical hoist line at the load Correct answer.

Explanation

Radius on a crane load chart is measured horizontally from the center of rotation (or tipping axis) to the hoist line, taken at the load hook. It is not the boom length, the boom-tip height, or a distance measured along the boom. Every capacity lookup is keyed to this horizontal value because it drives the load moment that the crane must resist.