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NCCER Mobile Crane study materials
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NCCER Mobile Crane practice questions

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Question 1Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Before a mobile crane begins lifting, the operator should verify that the crane is level within the manufacturer's tolerance primarily because an out-of-level condition does which of the following?

  1. Reduces the boom length needed to reach the pick point
  2. Automatically engages the anti-two-block device
  3. Increases the rated capacity shown on the load chart
  4. Shifts load and swing forces in directions the chart does not account for Correct answer.

Explanation

Load charts are built around a level machine; when the carrier is out of level, gravity and swing loads act along unintended axes, reducing stability and side-loading the boom. The chart values no longer represent the real geometry. Leveling is therefore a setup requirement, not a convenience.

Question 2Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A crane's load chart shows a capacity for a given radius and boom length. Which factor most directly determines the radius used for that chart entry during an actual pick?

  1. The horizontal distance from the center of rotation to the center of the load Correct answer.
  2. The vertical height of the boom tip above ground
  3. The length of wire rope paid out from the hoist drum
  4. The distance from the carrier's front bumper to the boom foot pin

Explanation

Load chart radius is measured horizontally from the crane's center of rotation to the vertical line through the load's center of gravity. Boom angle, boom length, and load position all combine to set that value. Using any other dimension misstates the capacity.

Question 3Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

During a pre-shift inspection, an operator finds the boom hoist wire rope has several broken outer wires clustered in one strand lay. What is the appropriate action?

  1. Remove the crane from service and follow the removal criteria for the rope Correct answer.
  2. Shorten the boom to reduce the load on that section of rope
  3. Coat the area with lubricant and resume lifting at reduced capacity
  4. Continue operating and note it on the next monthly inspection

Explanation

Clustered broken wires in one lay is a recognized removal criterion because the rope has lost a disproportionate share of its strength in a small area. The crane should be taken out of service until the rope is evaluated and replaced per the applicable standard. Lubricant or a shorter boom does not restore rope integrity.

Question 4Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

An operator is setting up on a site where the outrigger floats will bear on compacted fill over a buried utility trench. Which setup practice best addresses the risk?

  1. Keep the outriggers retracted and lift on tires within the chart
  2. Use blocking or mats sized to spread pressure and confirm the ground can carry it Correct answer.
  3. Lower the outriggers only on the side facing the load
  4. Fully extend all outriggers and rely on the float size to spread the load

Explanation

Outrigger floats concentrate high point loads, and fill over a trench can collapse under them. Adequate mats or cribbing spread the load, and the ground beneath must be verified as capable of supporting it. Setup on unverified fill is a common cause of crane overturns.

Question 5Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

What is the primary purpose of the anti-two-block device on a mobile crane?

  1. To limit swing speed when a load is at maximum radius
  2. To lock the outriggers during a lift
  3. To stop hoisting or boom lowering before the hook block contacts the boom tip Correct answer.
  4. To prevent the boom from being lowered too quickly

Explanation

The anti-two-block device senses when the hook block or ball approaches the boom tip and interrupts the functions that would bring them together. Contact can part the hoist rope and drop the load. It is a hoist/boom-lowering limiter, not a swing or outrigger control.

Question 6Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A lift plan shows a load weight of 9,000 lb and the chart capacity at the planned radius is 12,000 lb. The rigging and hook block add 1,500 lb. How should the operator evaluate the lift?

  1. Recompute, because total load including rigging exceeds the available margin Correct answer.
  2. Proceed only if the boom is fully retracted
  3. Recompute, because the chart already deducts rigging weight
  4. Proceed, because the load alone is below chart capacity

Explanation

Chart capacity must cover the total load: the payload plus rigging, hook block, and any attached below-the-hook devices. Here 9,000 plus 1,500 equals 10,500 lb, leaving only 1,500 lb of margin, which must also absorb dynamic and wind effects. The operator should verify the margin is adequate rather than compare only the payload.

Question 7Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

When is it acceptable to bypass or disable a crane's rated capacity limiter (load moment indicator)?

  1. Whenever the alarm is distracting to the crew
  2. When the operator is experienced and the load is light
  3. Only under the manufacturer's documented procedure for a specific function, with controls in place Correct answer.
  4. When the lift is short and the swing is slow

Explanation

The rated capacity limiter is a safety device, and defeating it removes the crane's primary overload protection. Any bypass must follow the manufacturer's written procedure, be limited to the specific function needed, and include compensating controls. Convenience or operator confidence is never a justification.

Question 8Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Which condition most requires the operator to stop a lift and reassess rather than continue at reduced speed?

  1. Slight hydraulic settling of the outrigger floats on firm mats
  2. A slow, smooth swing with the load close to the ground
  3. Normal engine temperature rise during a long pick
  4. A steady wind measured at the boom tip above the crane's rated wind speed Correct answer.

Explanation

Exceeding the manufacturer's rated wind speed increases the load's sail area and side loading on the boom beyond chart assumptions, so the lift must stop. Wind acts on both the load and the boom, and gusts can spike forces suddenly. The other conditions are normal operating observations.

Question 9Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

An operator must travel a rough, rutted haul road with the crane between picks. Which practice best protects the machine and the boom?

  1. Fully retract or stow the boom per the manufacturer's travel configuration and keep speed low Correct answer.
  2. Travel with the boom fully extended and elevated to clear obstacles
  3. Raise the outrigger beams but leave floats attached at full extension
  4. Carry the load in the hook while traveling to save a set-down

Explanation

Travel configuration is defined by the manufacturer and typically requires the boom retracted or stowed to limit bending and shock loads. Rough roads multiply dynamic forces, so speed must stay low. Carrying a suspended load while traveling is prohibited unless the crane and procedure specifically permit it.

Question 10Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

What does the term "quadrant" refer to when working with a mobile crane's load chart?

  1. The area of operation relative to the crane's chassis, such as over the front, side, or rear Correct answer.
  2. The four outrigger positions on the carrier
  3. The four sections of the telescopic boom
  4. The four sheave grooves in the hook block

Explanation

Load charts are often divided by area of operation because strength and stability differ depending on whether the boom works over the front, side, or rear of the carrier. Each quadrant may carry different capacity values. The operator must confirm which chart applies to the actual swing position.

Question 11Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A crane is rigged with a hook block whose weight is not shown on the chart's deduction table. What is the safest approach?

  1. Add it to the boom length instead of the load
  2. Estimate it as negligible compared with the load
  3. Ignore the hook block because it is part of the crane
  4. Obtain the actual weight and deduct it from the gross capacity before lifting Correct answer.

Explanation

Everything below the boom tip, including the hook block, is part of the gross load the chart capacity must support. If the weight is unknown, it must be determined rather than guessed. Underestimating it erodes the capacity margin and can lead to an overload.

Question 12Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

During shutdown at the end of a shift, what is the recommended practice for parking a mobile crane?

  1. Leave the boom elevated and the load on the hook overnight
  2. Leave outriggers extended on a slope to save setup time next shift
  3. Disconnect the battery and leave the boom at working radius
  4. Park on level ground, set the parking brake, and lower or stow the boom per the manufacturer Correct answer.

Explanation

End-of-shift shutdown should leave the crane stable and secure: level ground, parking brake or service brake set, and the boom lowered or stowed as the manufacturer specifies. This reduces the chance of wind, settling, or unauthorized movement causing an incident. Leaving a load suspended or the boom at working radius is unsafe.

Question 13Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Hand signals are being used because radio communication has failed. Which practice keeps the signal system safe?

  1. Any worker on the site may give signals as long as they are visible
  2. The operator follows the closest person's hand movements
  3. The rigger and the signalperson may both signal at the same time
  4. One designated signalperson gives signals, and the operator stops when signals are unclear Correct answer.

Explanation

A single designated signalperson prevents conflicting commands, and the operator must stop when a signal is not understood. Anyone may give an emergency stop signal, but routine direction comes from one person. Multiple signalers create ambiguity that can cause a wrong move.

Question 14Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A load is being landed on a flatbed trailer and the operator must make a small final adjustment. Which technique is appropriate?

  1. Lowering the load quickly and letting the riggers push it into position
  2. Rapid swing and plugging the swing brake to creep the load into place
  3. Extending the boom while the load rests on the trailer deck
  4. Slow, controlled movements with the load kept under positive control and tag lines as needed Correct answer.

Explanation

Final placement calls for slow, deliberate control so the load can be stopped and adjusted without shock loading the boom or rigging. Tag lines help control rotation without putting hands on the load. Shock or drag loads from abrupt moves can overload the crane.

Question 15Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Why does a mobile crane's capacity decrease as the load radius increases, even when the boom length is unchanged?

  1. The hook block becomes heavier as radius increases
  2. The overturning moment about the tipping axis grows with radius Correct answer.
  3. The wire rope stretches more at longer radius
  4. The hydraulic system loses pressure at longer radius

Explanation

Capacity at a given configuration is governed largely by stability: the moment created by the load equals load times radius about the tipping line. As radius grows, the same load produces a larger overturning moment, so the allowable load must fall. Structural limits may also govern, but stability explains the general trend.

Question 16Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

An operator plans a pick near the edge of a soft area where one outrigger float sinks slightly after the load is applied. What is the correct response?

  1. Continue the lift but reduce swing speed to compensate
  2. Lower the load, stop the lift, and re-set up with better ground support before continuing Correct answer.
  3. Extend that outrigger further to reach firmer ground
  4. Add counterweight to the rear to offset the sinking side

Explanation

Settling under load signals the ground is not carrying the outrigger pressure and the crane may be changing attitude, which invalidates the chart. The load should be set down and the setup corrected with proper mats or cribbing on verified ground. Continuing risks a progressive tip-over.

Question 17Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Before making a lift with a lattice boom crawler-mounted crane, the operator checks the boom stop and boom hoist limiting devices. Why are these checks important?

  1. They measure the load weight automatically
  2. They control the swing speed at maximum radius
  3. They prevent the boom from being raised past its design limit or lowered too far Correct answer.
  4. They level the crane on uneven ground

Explanation

Boom stops and boom hoist limiters keep the boom within its designed working range, preventing it from being pulled over backward or dropped too far. Exceeding those limits can collapse the boom. They do not perform weighing, leveling, or swing-speed functions.

Question 18Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A crane's load chart is based on a specific counterweight configuration. The crane is set up with less counterweight than the chart assumes. What is the effect?

  1. Capacity is unchanged because counterweight only affects travel
  2. Capacity decreases and the chart values no longer apply Correct answer.
  3. Capacity increases because the crane is lighter
  4. Capacity is unchanged as long as the outriggers are fully extended

Explanation

Counterweight contributes to the resisting moment that balances the load, so removing it reduces stability and therefore capacity. Charts are configuration-specific and do not apply when the counterweight does not match. The operator must use the chart for the actual configuration.

Question 19Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

During operation, the operator notices the boom is being side-loaded by a tag line pulled hard at an angle. Why is this a concern?

  1. Tag lines always increase the crane's rated capacity
  2. Side loading only affects the hook block, not the boom
  3. The boom is designed primarily for axial and vertical loads, and side loads can cause structural failure Correct answer.
  4. Side loading is accounted for in the chart's capacity values

Explanation

Boom strength is calculated for loads acting largely along its designed axes; a strong sideways pull introduces bending the chart does not cover. This can buckle or twist the boom even at loads well below chart capacity. Tag lines should guide the load gently, not drag it sideways.

Question 20Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Which item belongs on a pre-operation walkaround inspection of a mobile crane before the first lift of the day?

  1. The color of the load being lifted
  2. The number of workers on the site
  3. The lunch schedule of the rigging crew
  4. The condition of tires, outrigger pads, and hydraulic hoses for leaks or damage Correct answer.

Explanation

A pre-operation inspection covers the machine's condition: tires or tracks, outrigger pads and beams, hydraulic hoses for leaks or chafing, wire rope, and safety devices. These checks catch defects that could fail under load. Crew schedules and site headcount are not machine-condition items.

Question 21Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

An operator must pick a load whose weight is unknown and whose center of gravity is off-center. What is the most defensible course of action?

  1. Estimate the weight from its size and proceed at full chart capacity
  2. Lift one end first to feel the weight, then continue
  3. Use a longer sling so the off-center condition does not matter
  4. Determine the actual weight and rig so the load hangs level before lifting Correct answer.

Explanation

Unknown weight and an off-center center of gravity both defeat chart and rigging assumptions. The load must be weighed and rigged so it hangs level, distributing force as planned. Guessing or test-lifting can overload the crane or cause the load to shift suddenly.

Question 22Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Why must the outrigger beams be fully extended and the floats deployed per the manufacturer before lifting on a truck crane?

  1. Because the load charts assume that outrigger configuration for stability and structure Correct answer.
  2. To keep the tires from touching the ground during travel
  3. To increase the boom's lifting height
  4. To reduce the crane's overall width for transport

Explanation

Published capacities are tied to a specific outrigger configuration, usually fully extended with floats down. Partial extension changes the stability base and load paths, so the chart no longer applies. The operator must match the actual setup to the chart being used.

Question 23Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A crane is working near an energized overhead power line. Which practice reflects the standard approach to this hazard?

  1. Lower the boom and lift only with the hook close to the ground
  2. Rely on the operator to judge distance by eye during the swing
  3. Maintain the required minimum clearance, and if it cannot be maintained, de-energize or use a documented alternative with controls Correct answer.
  4. Ground the boom tip to the load to dissipate voltage

Explanation

The primary control is maintaining the required minimum approach distance from the line for the whole crane, boom, and load. If that distance cannot be kept, the line should be de-energized or other documented protective measures used. Visual judgment alone is unreliable, and grounding the boom does not make contact safe.

Question 24Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

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

  1. To compute and warn when the load approaches the crane's rated capacity for the current configuration Correct answer.
  2. To display boom angle only
  3. To record the number of lifts per shift
  4. To control the outrigger extension automatically

Explanation

The LMI uses boom length, angle, radius, and load sensing to compare the actual moment against the rated value for the configuration. It warns and then limits functions as capacity is approached. It is an overload protection aid, not a lift counter or outrigger control.

Question 25Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

An operator is asked to lift a load that requires the boom to pass over the cab of a truck parked in the swing path. What is the best planning decision?

  1. Swing over the truck because the load is light
  2. Have a worker hold the truck steady during the swing
  3. Barricade the swing path and move personnel and the truck out of the area before swinging Correct answer.
  4. Swing quickly so the load spends little time over the truck

Explanation

The swing path must be controlled so no one is under or near the load, and obstacles that could be struck or that block escape should be moved. Barricades keep personnel out of the fall zone. Swinging over a vehicle or having someone hold it exposes people to a dropped-load hazard.

Question 26Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A truck crane is being set up on a site where the ground surface is compacted gravel over undisturbed soil, but the outrigger floats must bear on it. Which setup step best confirms the ground can carry the outrigger loads before the first lift?

  1. Lower the outriggers only until the tires just clear the ground to reduce pad pressure
  2. Set the outriggers on the gravel without mats because gravel spreads load evenly
  3. Consult the manufacturer's ground bearing pressure data and verify the actual bearing area and soil condition Correct answer.
  4. Deploy floats and observe whether the pads settle during a test lift of the heaviest planned load

Explanation

Rated capacities assume the crane is level and the supporting surface can carry the outrigger reactions; the operator must compare calculated ground bearing pressure against the actual soil condition and pad area. Mats or cribbing are added when the surface cannot carry the load. Relying on a test lift or on gravel alone does not verify capacity and can lead to sudden settlement.

Question 27Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

During the pre-operation walkaround, an operator finds the wire rope on the main hoist has several broken outer wires clustered in one lay length. What is the correct action?

  1. Coat the area with lubricant to prevent further corrosion and continue
  2. Continue operating but reduce the load by half for the shift
  3. Remove the crane from service and have the rope evaluated against removal criteria Correct answer.
  4. Note it on the log and recheck at the end of the week

Explanation

Broken wires concentrated in one section, especially in one lay length, are a recognized rope removal criterion because they indicate localized strength loss. The crane should be taken out of service and the rope inspected against the manufacturer's and applicable standards before further lifting. Lubricant or load reduction does not restore rope integrity.

Question 28Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A crane's load chart gives a capacity for the machine on outriggers that are fully extended. The site is too narrow to extend them fully, so the operator plans to extend them only partway. How should the lift be planned?

  1. Use the on-rubber chart because partial extension behaves like tire support
  2. Use the chart for the shortest boom length as a conservative substitute
  3. Use the fully extended outrigger chart and reduce capacity by a fixed 25 percent
  4. Use the chart for the actual outrigger extension if the manufacturer publishes one, otherwise do not lift Correct answer.

Explanation

Charts are valid only for the configuration they describe, so partially extended outriggers require a manufacturer-published rating for that condition. If no such rating exists, the crane cannot be operated in that configuration for lifting. Applying arbitrary percentages or substituting another chart is not an approved method.

Question 29Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

An operator is about to swing a load and the only signal person is standing where the operator cannot see them for part of the swing. What is the correct practice?

  1. Complete the swing quickly so the load spends less time out of view
  2. Proceed and rely on the radio if the signal person has one
  3. Stop the swing until a signal person is in continuous view or an approved signal system is in place Correct answer.
  4. Have a nearby worker relay signals by voice from the blind area

Explanation

The operator must be able to receive signals continuously throughout the move, either by direct sight or by a reliable, agreed communication method. If the signal person will be out of view, the lift should not proceed until communication is restored. Voice relay and speed are not substitutes for a controlled signal system.

Question 30Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A mobile crane is being operated on a slope that exceeds the limit stated in the manufacturer's operating manual. What is the correct response?

  1. Operate at reduced boom length to compensate for the slope
  2. Operate only while swinging uphill
  3. Do not operate the crane until it can be set up within the stated slope limit Correct answer.
  4. Chock the downhill tires and proceed at crawl speed

Explanation

Leveling and slope limits in the manufacturer's manual are conditions of the crane's rating; exceeding them invalidates the capacity charts and creates tipping and swing-control problems. The crane must be repositioned or the site regraded so it can be set within limits. Boom length, swing direction, or chocking do not restore the rating.

Question 31Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A crane is set up beside an excavation, and the outrigger float nearest the edge bears on soil that may have been undermined. Which approach best addresses the hazard?

  1. Set the float on a single timber mat and proceed with the planned lift
  2. Move the crane back so the outrigger is on verified competent ground or use an engineered support Correct answer.
  3. Reduce the boom radius slightly and keep the float near the edge
  4. Place the float and monitor it visually throughout the shift

Explanation

Ground near an excavation may be undercut or lose bearing capacity when loaded, so the crane must be positioned where the outrigger reaction is carried by verified competent soil or an engineered pad. Visual monitoring and a single mat do not provide the needed bearing verification. Reducing radius does not remove the risk of the edge failing.

Question 32Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Which action is required before the operator leaves the crane at the end of a shift with a load still suspended?

  1. Leave the load suspended only if the wind is below the chart limit
  2. Lower the load to the ground, land it, and relieve the hoist line before leaving the controls Correct answer.
  3. Leave the load suspended with the brake set and the controls locked
  4. Leave the load suspended but post a watchman until the next shift

Explanation

A suspended load must never be left unattended; the operator lands the load, slackens the hoist line, and secures the crane before leaving. Leaving a load hanging keeps stored energy in the system and exposes anyone nearby to a dropped load. A watchman or calm wind does not make an unattended suspended load acceptable.

Question 33Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

During a pick, the operator must boom down to place a load beyond a wall. What effect does booming down have on the load radius and the crane's capacity?

  1. Radius increases and capacity decreases Correct answer.
  2. Radius increases but capacity is unaffected if the boom angle is above 45 degrees
  3. Radius decreases and capacity increases
  4. Radius stays the same because the load line length is unchanged

Explanation

Boiling down lowers the boom angle, which moves the load farther from the crane's center of rotation, so radius grows. Because capacity falls as radius increases, the chart must be checked at the larger radius before the move. Load line length and a fixed boom-angle threshold do not override that relationship.

Question 34Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A crane's anti-two-block device is found to be inoperative during the pre-operation check. What is the correct action?

  1. Operate with a spotter watching the head and the block
  2. Operate only with the boom at a low angle to reduce the risk
  3. Tag the crane out of service and repair the device before lifting Correct answer.
  4. Operate only at slow hoist speed until repairs are made

Explanation

The anti-two-block device is a required safety device that prevents the hook block from contacting the boom tip and damaging the rope. An inoperative device makes the crane unsafe to operate and it must be removed from service until repaired. Spotters, slow speeds, or boom angle do not replace the device.

Question 35Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A crane is being used to lift a load from a barge alongside a dock. Which factor most changes the capacity planning compared with the same lift on land?

  1. The number of tag lines attached to the load
  2. The crane's swing bearing temperature
  3. The color of the load being lifted
  4. The possibility that the barge or dock moves and changes the load radius and list Correct answer.

Explanation

When the crane or the load is on a floating or movable surface, movement changes the radius and can introduce list, so the lift must be planned for the worst position and often with reduced ratings. Swing bearing temperature, load color, and tag line count do not drive capacity in that way.

Question 36Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Which practice best protects personnel who must work under a load being landed on a truck bed?

  1. Allow workers under the load only while it is within 3 feet of the bed
  2. Keep personnel out from under the suspended load and use tag lines from outside the drop zone Correct answer.
  3. Let workers guide the load by hand once it is close to the bed
  4. Permit workers under the load if they wear hard hats

Explanation

No one should stand or pass under a suspended load, and tag lines let workers control rotation from a safe distance outside the drop zone. Proximity to the landing point, hard hats, or hand guiding do not make standing under a load acceptable.

Question 37Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

An operator is setting up a lattice boom crane and must decide whether the boom hoist limiting device is functioning. Why is this device important during setup and operation?

  1. It limits the swing speed when the boom is long
  2. It prevents the load from exceeding the chart capacity
  3. It stops the boom from being raised beyond the maximum angle and prevents boom damage Correct answer.
  4. It limits how far the boom can be lowered and prevents the boom from contacting the ground

Explanation

The boom hoist limiting device stops hoisting of the boom at the maximum permissible angle, protecting the boom and pendant system from overstress. It does not control lowering, swing speed, or load weight. Rated capacity is monitored by the load moment indicator and the operator's chart use.

Question 38Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

A load must be picked from a position where the boom will pass close to a building wall. Which planning step best reduces the chance of contact during the swing?

  1. Remove the tag lines so they cannot catch on the wall
  2. Plan the swing path and set up so the boom has adequate clearance, using a controlled swing with a spotter if needed Correct answer.
  3. Lower the boom to the minimum angle to gain clearance
  4. Swing fast through the close area to minimize time near the wall

Explanation

Swing paths must be planned so the boom, load, and rigging clear all obstructions, and a spotter or controlled slow swing is used where clearance is tight. Speed, lowering the boom, or removing tag lines increases risk rather than controlling it.

Question 39Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

An operator notices the crane's load moment indicator shows a capacity reading but the boom length displayed does not match the actual boom configuration. What is the correct action?

  1. Recalibrate or correct the LMI setup before lifting, and do not lift until it matches the actual configuration Correct answer.
  2. Ignore the boom length and use only the radius display
  3. Continue lifting because the LMI is still displaying a capacity value
  4. Reduce the load by 10 percent and continue

Explanation

The LMI must be set for the actual boom configuration; an incorrect boom length means the displayed capacity is not valid for the crane as rigged. Lifting must stop until the system is corrected and verified. A displayed number, partial use of the display, or a fixed load reduction does not make an improperly configured LMI acceptable.

Question 40Mobile Crane Operation (site preparation, setup, inspection, operation, shutdown)

Before making the first lift of the day with a hydraulic truck crane, which check confirms the outriggers are properly set?

  1. Floats placed without mats on any firm-looking surface
  2. Outriggers extended until the tires just touch the ground
  3. All beams extended per the manufacturer, floats deployed, and the crane level on its bubble level Correct answer.
  4. Only the front outriggers deployed with the rear tires carrying the load

Explanation

Proper outrigger setup means full extension as specified, floats deployed, and the crane leveled using its level indicator, with suitable support under the floats. Partial deployment, tires carrying load, or unverified surfaces take the crane outside its rated configuration.

Question 41Rigging and Load Handling

Before lifting a load with a mobile crane, the load's weight must be compared against which value to confirm the lift is acceptable?

  1. The crane's rated capacity for the actual configuration and radius Correct answer.
  2. The crane's gross vehicle weight rating
  3. The counterweight's shipping weight
  4. The boom's bare weight

Explanation

Rated capacity is the maximum load the crane may handle for a specific boom length, radius, and configuration, as shown on the load chart. The load weight plus all rigging and lifting attachments must not exceed that value. Gross vehicle weight, counterweight weight, and bare boom weight do not describe lifting capability at a given radius.

Question 42Rigging and Load Handling

A load weighs 9,000 lb and the rigging (sling, shackles, and hook block allowance) adds 1,000 lb. What is the total load that must be checked against the crane's rated capacity?

  1. 8,000 lb
  2. 10,000 lb Correct answer.
  3. 9,000 lb
  4. 1,000 lb

Explanation

The load chart capacity must cover the total suspended weight, which includes the load plus all rigging and lifting attachments below the boom tip. Adding 9,000 lb and 1,000 lb gives 10,000 lb. Using only the bare load weight understates the demand on the crane and is a common cause of overload.

Question 43Rigging and Load Handling

On a mobile crane load chart, what does the working radius represent?

  1. The distance between the front and rear outriggers
  2. The length of boom extended from the boom foot
  3. The vertical height of the boom tip above ground
  4. The horizontal distance from the crane's rotation center to the center of the suspended load Correct answer.

Explanation

Working radius is measured horizontally from the axis of rotation to the vertical line through the load's center of gravity. Capacity decreases as radius increases, so accurate radius measurement is essential. Boom length, tip height, and outrigger spread are separate dimensions that do not define radius.

Question 44Rigging and Load Handling

What is the primary purpose of using a properly sized spreader beam in a two-leg lift?

  1. To keep the sling legs more vertical and reduce horizontal compressive force on the load Correct answer.
  2. To increase the crane's rated capacity
  3. To shorten the effective boom length
  4. To eliminate the need for a load chart

Explanation

A spreader beam holds the sling legs apart at the top so they hang closer to vertical, which reduces the horizontal squeezing force on the load and lowers tension in each leg. It does not change the crane's capacity or the load chart requirement. The beam itself adds weight that must be included in the total load.

Question 45Rigging and Load Handling

A wire rope sling shows several broken wires clustered in one strand and evidence of kinking. What is the correct action?

  1. Shorten it by tying a knot to bypass the damaged section
  2. Remove it from service and have it inspected or destroyed per the removal criteria Correct answer.
  3. Continue using it if the load is under half of rated capacity
  4. Use it for this lift only, then tag it for inspection

Explanation

Broken wires concentrated in one strand and kinking are removal-from-service conditions for wire rope slings. The sling must be taken out of service and evaluated against removal criteria, then repaired, downgraded, or destroyed. Knots are never permitted in slings, and reduced load does not make damaged rigging acceptable.

Question 46Rigging and Load Handling

When a two-leg sling bridle has legs at a 60-degree angle from horizontal, what happens to the tension in each leg compared with a vertical single-leg lift of the same load?

  1. Tension in each leg decreases below half the load weight
  2. Tension in each leg increases because the legs share the load at an angle Correct answer.
  3. Tension in each leg equals the full load weight
  4. Tension is unaffected by sling angle

Explanation

As sling legs move away from vertical, each leg carries more tension for the same vertical load because only the vertical component supports the weight. At 60 degrees from horizontal, each leg tension equals the load divided by the sine of 60 degrees and by the number of legs, which exceeds a simple half-load share. Sling angle is therefore a critical rigging variable.

Question 47Rigging and Load Handling

What is the function of a tag line during a mobile crane lift?

  1. To measure the load's weight during the lift
  2. To add lifting capacity to the crane
  3. To control load rotation and sway from a safe distance Correct answer.
  4. To secure the load to the boom

Explanation

A tag line lets a rigger guide and steady the load from outside the fall zone, preventing rotation and swing that could strike people or structures. It is a control aid only and carries no lifting duty. It does not measure weight or attach the load to the boom.

Question 48Rigging and Load Handling

A crane's load chart shows a capacity of 12,000 lb at a 20 ft radius and 9,500 lb at a 25 ft radius. If the total load is 10,000 lb, what does this indicate?

  1. The lift is acceptable at both radii
  2. The lift is acceptable at 20 ft radius but exceeds capacity at 25 ft radius Correct answer.
  3. The lift is unacceptable at both radii
  4. The lift is acceptable at 25 ft radius but not at 20 ft radius

Explanation

Capacity falls as radius grows, so the 10,000 lb load fits within the 12,000 lb rating at 20 ft but exceeds the 9,500 lb rating at 25 ft. The operator must keep the actual working radius within the range where capacity covers the total load. This illustrates why radius must be verified before and during the lift.

Question 49Rigging and Load Handling

What does the term "center of gravity" of a load describe?

  1. The heaviest corner of the load
  2. The point where the load's weight is evenly balanced in all directions Correct answer.
  3. The highest point on the load
  4. The point where the load attaches to the hook

Explanation

The center of gravity is the point at which the load's weight is balanced, so the hook must be positioned over it to keep the load level. If the hook is offset from the center of gravity, the load will tilt and shift. Identifying it is essential for stable, predictable lifts.

Question 50Rigging and Load Handling

A load has an off-center center of gravity, so one sling leg will carry more tension than the other. What is the best rigging practice?

  1. Reduce the load weight by 10 percent to compensate
  2. Assume both legs share the load equally
  3. Size each sling leg for the maximum tension it will carry and position the hook over the center of gravity Correct answer.
  4. Use a single vertical sling to avoid imbalance

Explanation

When the center of gravity is off-center, the leg nearer the center of gravity carries more tension, so each leg must be rated for its actual share. Positioning the hook over the center of gravity also minimizes tilt and load shift. Equal-share assumptions are unsafe for unbalanced loads.