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NCCCO Digger Derrick study materials
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NCCCO Digger Derrick practice questions

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Question 1Site Evaluation, Setup, and Ground Conditions

Before a digger derrick begins work, the operator finds the utility locate marks were painted more than two weeks ago and the paint is faded. What is the correct action?

  1. Photograph the faded marks and proceed with hand digging only
  2. Begin work carefully, staying a safe distance from any faint marks
  3. Proceed if the utility owner confirms nothing has changed by phone
  4. Request a re-locate and wait for fresh markings before augering Correct answer.

Explanation

Locate markings have a limited validity period, and faded or expired markings must be refreshed before excavation. State law and the utility owner's ticket system govern how long marks remain valid, so the operator must request a new locate and wait for it. Augering into a pole hole is excavation and is covered by these requirements.

Question 2Site Evaluation, Setup, and Ground Conditions

When setting up a digger derrick on a slope, which practice best protects against the unit sliding or tipping?

  1. Lower the boom to the ground and rely on the boom as a stabilizer
  2. Fully extend the outriggers on the downhill side only
  3. Chock the wheels, set outriggers on firm bearing, and verify the bubble level Correct answer.
  4. Set the parking brake and skip outriggers to keep the load low

Explanation

Setup on a slope requires controlling both sliding and tipping: wheels should be chocked or otherwise restrained, outriggers must bear on firm material, and the level indicator confirms the unit is within the manufacturer's limits. Extending only one side or skipping outriggers defeats the stability system.

Question 3Site Evaluation, Setup, and Ground Conditions

The load-bearing capacity of the soil at a setup location is uncertain. Which approach is most consistent with safe digger derrick setup?

  1. Set the outriggers on the spoil pile to keep them out of traffic
  2. Use larger outrigger pads to spread the load and confirm bearing capacity Correct answer.
  3. Place the outriggers in the nearest ditch for a lower center of gravity
  4. Assume average soil strength and set outriggers normally

Explanation

Outrigger float area must be matched to the bearing strength of the ground so the reaction force does not punch through or settle. Larger pads reduce unit ground pressure, but the operator still needs confirmation that the soil can carry the load. Uncertain bearing capacity is a reason to verify, not to assume.

Question 4Site Evaluation, Setup, and Ground Conditions

Why must the digger derrick be positioned so the pole hole is within the reach of the boom and auger without repositioning the truck?

  1. It eliminates the need for a spotter during the lift
  2. It allows the operator to skip the pre-lift walk-around inspection
  3. It keeps the pole handling operation within the rated capacity and stability envelope Correct answer.
  4. It reduces the number of outrigger pads needed

Explanation

Working position determines the load radius, which directly affects capacity. Keeping the hole and pole placement inside the planned working envelope means the machine stays within its rated capacity and stability limits for every phase of the job. Repositioning under load is a leading cause of tipovers.

Question 5Site Evaluation, Setup, and Ground Conditions

A digger derrick is set up near the edge of an open trench. What is the primary concern for the setup?

  1. The trench wall or edge may fail and undermine the outrigger support Correct answer.
  2. The trench may provide drainage that softens the outrigger pads
  3. The trench edge makes the level indicator read incorrectly
  4. The trench will block radio communication with the ground crew

Explanation

Ground near an excavation edge is often disturbed or undercut and can collapse under the concentrated outrigger reaction. The setup must be far enough back that the outriggers bear on stable, undisturbed soil, and the excavation must be evaluated for slope stability.

Question 6Site Evaluation, Setup, and Ground Conditions

Which document should the operator consult to determine the digger derrick's capacity at a specific boom radius and outrigger configuration?

  1. The vehicle registration and weight certificate
  2. The utility's switching order for the day
  3. The load chart for that configuration Correct answer.
  4. The annual third-party inspection report

Explanation

The load chart states rated capacity for each boom length, radius, and outrigger setup, and it is the authority for whether a planned lift is within rating. Inspection reports, registration documents, and switching orders serve other purposes and do not contain capacity data.

Question 7Site Evaluation, Setup, and Ground Conditions

During setup, the operator notices an overhead power line near the intended boom path. What is the correct first step?

  1. Proceed and keep the boom below the line at all times
  2. Wrap the boom in insulating blankets and continue
  3. Ask the ground crew to watch the boom and wave if it gets close
  4. Stop and establish the required clearances or arrange a de-energization before proceeding Correct answer.

Explanation

Energized lines near the working envelope are a serious hazard, and the required approach distance must be maintained by design, not by operator judgment in the moment. If the planned work cannot keep the required clearance, the line must be de-energized or otherwise protected per the applicable rules.

Question 8Site Evaluation, Setup, and Ground Conditions

Which condition most directly reduces the effective bearing area under an outrigger float?

  1. A freshly painted outrigger pad
  2. Soft, recently disturbed backfill Correct answer.
  3. A light wind from the side
  4. A slight crown in the pavement

Explanation

Effective bearing area depends on the ground beneath the float; loose or recently disturbed backfill compacts or shears under load, reducing support. That is why backfilled areas near new construction require evaluation before setup.

Question 9Site Evaluation, Setup, and Ground Conditions

An operator is setting up on a concrete driveway and is unsure whether the slab can carry the outrigger loads. Which action is most appropriate?

  1. Assume the slab is adequate because it is concrete
  2. Place the outriggers over an expansion joint for even loading
  3. Set the outriggers at the slab edge for maximum reach
  4. Evaluate the slab, use load-spreading pads, and consider the void beneath Correct answer.

Explanation

Concrete slabs, especially over basements or culverts, may be thin or unsupported and can crack or collapse under concentrated outrigger loads. The operator should evaluate the slab and spread the load, taking into account any void underneath.

Question 10Site Evaluation, Setup, and Ground Conditions

What is the purpose of performing a pre-setup walk-around of the intended work area?

  1. To identify hazards such as soft ground, overhead lines, and traffic before committing the unit Correct answer.
  2. To confirm the load chart matches the boom length
  3. To decide which crew member will operate the auger
  4. To satisfy the daily equipment maintenance checklist

Explanation

The walk-around is a hazard survey of the specific location: ground conditions, overhead and underground hazards, access, and traffic control. Findings drive where the unit is set up and what controls are needed before work begins.

Question 11Site Evaluation, Setup, and Ground Conditions

The outrigger pad on one corner sinks several inches shortly after the boom is raised. What should the operator do?

  1. Add cribbing under the pad while the boom remains raised
  2. Continue if the bubble level still shows level
  3. Reduce boom radius and finish the lift quickly
  4. Lower the boom, retract, and re-set up on improved bearing support Correct answer.

Explanation

Settlement means the ground cannot support the reaction, and stability is compromised. The load must be lowered and the unit re-set up on ground that has been improved or on properly sized pads before work resumes. Making adjustments under a raised load is unsafe.

Question 12Site Evaluation, Setup, and Ground Conditions

Which factor most affects the size of outrigger pads needed at a given location?

  1. The outrigger reaction force and the allowable ground bearing pressure Correct answer.
  2. The color of the pad and its visibility to traffic
  3. The length of the boom being used for the lift
  4. The number of crew members standing nearby

Explanation

Pad size is chosen so the outrigger reaction divided over the pad area stays below the ground's allowable bearing pressure. Softer ground or higher reactions require larger effective pad area. Pad visibility and crew count do not enter the calculation.

Question 13Site Evaluation, Setup, and Ground Conditions

A digger derrick must be set up on a street with passing traffic. Which control is most appropriate?

  1. Set up during a lull in traffic and begin work immediately
  2. Rely on the crew's high-visibility vests to warn drivers
  3. Establish traffic control with signs, cones, and flaggers as needed before setup Correct answer.
  4. Park a second truck in the travel lane as a barrier without warning devices

Explanation

Work zones require planned traffic control so drivers are warned and guided around the setup and the crew has a protected work area. Vests alone do not slow or redirect traffic, and an unmarked vehicle is not an adequate barrier.

Question 14Site Evaluation, Setup, and Ground Conditions

Why is it important to confirm that all outriggers are fully deployed and pinned or otherwise secured before lifting?

  1. It allows the boom to reach farther than the load chart shows
  2. It keeps the outrigger pads clean
  3. It reduces fuel consumption during the lift
  4. Partially deployed outriggers reduce the machine's stability and rated capacity Correct answer.

Explanation

The load chart assumes a specific outrigger configuration, and partial deployment reduces the machine's footprint and stability. Outriggers must be fully extended and secured as the manufacturer requires before the boom is loaded.

Question 15Site Evaluation, Setup, and Ground Conditions

The ground at a setup site is frozen at the surface but thawed below. What risk does this present?

  1. Frost has no effect on outrigger bearing as long as pads are used
  2. The frozen crust may appear firm but can fail when the thawed layer compresses Correct answer.
  3. Frozen ground always increases capacity, so no evaluation is needed
  4. The thawed layer will improve drainage and stabilize the outriggers

Explanation

A frozen surface crust can mask soft, thawed soil beneath, and the concentrated outrigger load can break through the crust or cause the thawed layer to consolidate unevenly. The site must be evaluated for the actual subsurface condition, not just the surface.

Question 16Site Evaluation, Setup, and Ground Conditions

When planning a setup, what does the term 'working envelope' most accurately describe for a digger derrick?

  1. The area occupied by the truck and outriggers on the ground
  2. The distance the auger can drill in a single pass
  3. The zone the boom and load can reach while staying within rated capacity and clearances Correct answer.
  4. The radius within which the crew may stand during a lift

Explanation

The working envelope is the planned region of boom and load movement that stays within the load chart and maintains required clearances from hazards such as energized lines. It defines where the load may go, not just where the machine sits.

Question 17Site Evaluation, Setup, and Ground Conditions

An operator must set up on a site where the only level area is directly beneath a high-voltage line. What is the best course of action?

  1. Set up there and rely on the line's height above the boom
  2. Set up there but limit lifts to light poles only
  3. Set up there and lower the boom whenever a vehicle passes
  4. Find an alternate location or arrange line de-energization or guarding before setup Correct answer.

Explanation

If the required clearance cannot be maintained from the level area, the setup must move or the line must be de-energized or guarded per the applicable rules. Light loads and vehicle traffic do not change the clearance requirement, and height alone is not a reliable safeguard.

Question 18Site Evaluation, Setup, and Ground Conditions

Which practice best verifies that the outrigger pads are in full contact with the ground?

  1. Visually check each pad after partial loading and adjust before full boom extension Correct answer.
  2. Assume contact is adequate once the outrigger beam is extended
  3. Check contact only after the first pole is set
  4. Kick each pad to feel for movement after the boom is fully loaded

Explanation

Pads should be checked for full contact as the outriggers take load, before the boom is fully extended and the machine is committed. Adjustments are made while the outrigger is lightly loaded, not after the unit is fully set up.

Question 19Site Evaluation, Setup, and Ground Conditions

A crew plans to set up beside a septic tank or underground vault whose location is known. What is the primary concern?

  1. The buried structure may collapse under outrigger loads, so the setup must avoid it Correct answer.
  2. The tank may attract groundwater that softens the pads
  3. The tank will interfere with radio signals to the operator
  4. The vault will make the load chart inaccurate

Explanation

Buried structures such as tanks, vaults, and culverts are voids or thin covers that can collapse under concentrated outrigger reactions. The setup must be positioned so outriggers bear on solid ground away from the structure.

Question 20Site Evaluation, Setup, and Ground Conditions

An operator arrives at a job site after heavy rain and finds standing water around the intended outrigger positions. What is the most appropriate response?

  1. Pump the water away and set up immediately without further evaluation
  2. Set up as planned because the outriggers will displace the water
  3. Reduce the load and set up in the water
  4. Relocate to firmer ground or improve the bearing area before setup Correct answer.

Explanation

Standing water indicates saturated soil, which loses bearing strength and is prone to settlement and lateral failure under outrigger loads. The unit should be relocated to firmer ground or the bearing area improved and verified before setup. Pumping water off does not restore soil strength.

Question 21Site Evaluation, Setup, and Ground Conditions

What is the main reason for verifying that the digger derrick's level indicator reads level before augering a pole hole?

  1. Leveling is required only when lifting poles, not when augering
  2. The level indicator controls the auger's rotation speed
  3. An unlevel unit places the auger and pole out of plumb and loads the machine unevenly Correct answer.
  4. A level unit drills faster in rocky soil

Explanation

A level machine keeps the auger and the resulting hole plumb and distributes reactions evenly through the outriggers. Operating out of level introduces side loads and reduces the stability margin for both drilling and lifting.

Question 22Site Evaluation, Setup, and Ground Conditions

Two outrigger positions are available: one on undisturbed native soil and one on compacted fill placed last month. Which choice is more defensible, and why?

  1. Either one, because outrigger pads equalize all ground conditions
  2. The fill, because it is closer to the pole hole
  3. The native soil, because recently placed fill may not have reached design strength Correct answer.
  4. The fill, because compaction always exceeds native soil strength

Explanation

Recently placed fill may not have consolidated or reached its specified density, so it can settle under load even if it was compacted in lifts. Undisturbed native soil is generally the more predictable support unless testing shows the fill is adequate.

Question 23Site Evaluation, Setup, and Ground Conditions

A digger derrick is set up on a crowned asphalt road, and the operator wants to level the unit using the outriggers. Which consideration is most important?

  1. The level indicator can be ignored on paved surfaces
  2. The outrigger on the low side may need to extend farther, reducing pad contact and beam support Correct answer.
  3. The crown improves drainage and therefore increases bearing capacity
  4. Cribbing under the high-side outriggers is always prohibited

Explanation

Leveling on a crown often requires unequal outrigger extension, and an over-extended beam or a pad that only partly contacts the slope reduces support and can induce side loads. The operator must ensure each outrigger is properly supported and within its permitted extension.

Question 24Site Evaluation, Setup, and Ground Conditions

During a site survey, the operator identifies a buried fiber optic line with no visible surface markings. What is the most appropriate action before augering?

  1. Proceed because fiber optic lines are not hazardous to equipment
  2. Stop and obtain a valid locate and clearance for the line before excavation Correct answer.
  3. Auger a smaller-diameter hole to reduce the chance of contact
  4. Ask the property owner to point out where the line runs

Explanation

Unmarked buried facilities require a locate and clearance before excavation, regardless of the utility type. Striking a fiber line can injure workers and disrupt critical services, and the operator must not rely on guesswork or verbal directions.

Question 25Site Evaluation, Setup, and Ground Conditions

An operator must choose between two setups: Setup A keeps the pole hole at a longer radius but on firm ground; Setup B places the hole at a shorter radius but requires outriggers on soft ground with larger pads. Which analysis is most appropriate?

  1. Compare the rated capacity at each radius against the ground support each setup can provide Correct answer.
  2. Choose A because firm ground eliminates the need to check the load chart
  3. Choose either, since pad size and radius do not interact
  4. Choose B solely because the shorter radius always means a higher capacity

Explanation

Safe setup requires both sufficient capacity at the working radius and adequate ground support for the resulting reactions. A shorter radius raises capacity but is worthless if the ground cannot carry the outrigger loads, so the two factors must be evaluated together.

Question 26Site Evaluation, Setup, and Ground Conditions

Before an outrigger is extended on a digger derrick, what does the manufacturer's load chart require the operator to confirm about the setup surface?

  1. That the surface has been swept free of loose gravel and debris
  2. That the surface is covered by a protective mat of any thickness
  3. That the surface and subsurface can support the imposed outrigger loads Correct answer.
  4. That the surface slopes downward away from the truck frame

Explanation

Load charts and stability calculations assume the outrigger floats bear on material strong enough to resist the imposed pressure without settling. If the soil or slab cannot carry that load, capacity figures no longer apply and the unit may tip or the outrigger may punch through. Surface cleanliness and slope are separate concerns from bearing strength.

Question 27Site Evaluation, Setup, and Ground Conditions

An operator must position a digger derrick near the edge of an unshored excavation. Which placement practice best protects against a slope failure under the outrigger?

  1. Locate the outrigger well back from the edge and account for the soil's angle of repose Correct answer.
  2. Set the outrigger float as close to the edge as possible to shorten the boom radius
  3. Bridge the excavation edge with steel plate and place the float on the plate
  4. Rely on the spoil pile beside the trench to buttress the outrigger pad

Explanation

An excavation removes lateral support from the adjacent soil, so the ground near the edge can shear away under outrigger pressure. Keeping the float back from the edge, beyond the zone influenced by the cut, keeps the pad on competent material. The setback distance should reflect soil type and depth of the excavation.

Question 28Site Evaluation, Setup, and Ground Conditions

A digger derrick is to be set up on a slope too steep for the outriggers to level the unit within the manufacturer's limits. What is the correct course of action?

  1. Relocate to a flatter area or build a properly engineered, compacted pad Correct answer.
  2. Level the unit with the outriggers and accept a small frame tilt
  3. Chock the wheels and operate with the outriggers partly deployed
  4. Extend the uphill outriggers fully and leave the downhill ones retracted

Explanation

Outriggers are leveling devices within a limited range, not a means of compensating for a badly sloped site. Operating outside the manufacturer's leveling limits loads the boom, turntable, and chassis in ways the capacity ratings do not cover. The remedy is to move to acceptable ground or to prepare a stable, level pad.

Question 29Site Evaluation, Setup, and Ground Conditions

Why must the operator check for underground utilities before positioning outrigger floats at a setup site?

  1. Buried lines interfere with the radio remote signal used to control the boom
  2. Utilities must be marked so the crew knows where to store spoils
  3. Utility locating is required only when the auger will penetrate the ground
  4. Outrigger pressure can crush buried lines or collapse a vault beneath the float Correct answer.

Explanation

Concentrated outrigger loads are transmitted into the ground and can damage or rupture buried pipe, cable, or a vault roof directly beneath the float. A collapse under a float also removes the machine's support. Locating and marking utilities lets the operator choose float positions that avoid these hazards.

Question 30Site Evaluation, Setup, and Ground Conditions

An operator is comparing two setups on the same site. Setup A places the outrigger floats on undisturbed native soil. Setup B places them on a recently backfilled utility trench that appears level and dry. How should the operator evaluate the two?

  1. Setup B is preferable because backfill has already been compacted by the excavator
  2. Setup B is acceptable if the outrigger floats are enlarged to cover the trench width
  3. The two are equivalent if both appear level and the pads are the same size
  4. Setup A is preferable because undisturbed soil is more likely to carry the load without settling Correct answer.

Explanation

Recent backfill, even when it looks level and dry, is usually looser and less uniform than native soil and can consolidate under load. Differential settlement at one float tilts the machine and shifts load to other outriggers. Native undisturbed ground is the more reliable bearing material unless the fill has been tested and prepared.

Question 31Digger Derrick Components, Terminology, and Load Charts

On a digger derrick load chart, what does the boom angle row or column represent?

  1. The angle of the boom measured from horizontal Correct answer.
  2. The angle of the auger flighting relative to the ground
  3. The tilt of the carrier frame on a slope
  4. The rotation of the turntable from its stowed position

Explanation

Boom angle is measured between the boom centerline and horizontal, and capacity decreases as the boom approaches horizontal because the load radius increases. Operators match the boom angle indicator reading to the chart to find the correct capacity row.

Question 32Digger Derrick Components, Terminology, and Load Charts

What is the load radius on a digger derrick capacity chart?

  1. The vertical height of the boom tip above the ground
  2. The distance from the front bumper to the outrigger pad
  3. The length of boom extended from the boom pivot
  4. The horizontal distance from the center of rotation to the center of the load Correct answer.

Explanation

Radius is a horizontal measurement taken from the crane's center of rotation to the vertical line through the load's center of gravity. It is not the same as boom length or boom tip height, and it grows as the boom is lowered.

Question 33Digger Derrick Components, Terminology, and Load Charts

Which component transfers lifting force from the boom tip down to the load line on a digger derrick?

  1. The auger torque tube
  2. The rotation gearbox
  3. The outrigger beam lock pin
  4. The boom tip sheave and wire rope Correct answer.

Explanation

The boom tip sheave guides the wire rope, and the rope transmits the lifting force to the load line and hook. Sheaves and rope are part of the lifting system, while the other items serve auger drive, outrigger, or swing functions.

Question 34Digger Derrick Components, Terminology, and Load Charts

A digger derrick is equipped with a boom tip winch and a separate digger winch. What is the primary purpose of the digger winch?

  1. To lift the maximum rated load at full radius
  2. To raise and lower the pole being set
  3. To hoist personnel in a platform
  4. To control the auger during drilling Correct answer.

Explanation

The digger winch raises and lowers the auger and controls its feed rate during drilling. It is not rated for general lifting, and the boom tip winch handles hoisting and pole setting.

Question 35Digger Derrick Components, Terminology, and Load Charts

What is the function of the outriggers on a digger derrick?

  1. To raise the auger clear of the hole
  2. To increase the carrier's road speed
  3. To provide a stable base and level the unit during lifting and digging Correct answer.
  4. To extend the boom's hydraulic reach

Explanation

Outriggers widen the support base and level the carrier so that the load chart capacities apply. Capacities are only valid when outriggers are fully extended and set per the manufacturer's instructions.

Question 36Digger Derrick Components, Terminology, and Load Charts

A capacity chart shows capacities for two boom sections, one retracted and one extended. Why do the capacities differ?

  1. The retracted boom uses a different wire rope size
  2. The extended boom has a shorter effective radius
  3. The extended boom reduces the counterweight requirement
  4. The extended boom places more load on the boom structure and increases tipping moment Correct answer.

Explanation

Extending the boom increases the radius and the bending load on the boom, so the chart lists lower capacities for the extended configuration. The operator must use the row matching the actual boom configuration.

Question 37Digger Derrick Components, Terminology, and Load Charts

The boom angle indicator reads 45 degrees and the load radius is 20 feet. Which chart entry should be used to determine capacity?

  1. The capacity for the longest boom length available
  2. The 45-degree row at the 20-foot radius column Correct answer.
  3. The capacity for the smallest radius listed
  4. The maximum capacity listed anywhere on the chart

Explanation

Capacity is read at the intersection of the actual boom angle (or boom length) and the actual load radius. Using any other entry overstates capacity and is unsafe.

Question 38Digger Derrick Components, Terminology, and Load Charts

A digger derrick chart is rated for 8,000 pounds at a 10-foot radius with outriggers set. The load weighs 6,500 pounds, and rigging adds 400 pounds. What is the correct interpretation?

  1. The lift exceeds capacity because total load is 6,900 pounds against a deduction for the load line Correct answer.
  2. The lift is acceptable because rigging weight is excluded from capacity
  3. The lift is acceptable because the load alone is under capacity
  4. The lift requires only that the boom be kept above 60 degrees

Explanation

Rigging and load-handling devices must be counted as part of the load, and many charts also require deducting the weight of the load line and hook from the gross capacity. The combined weight must be compared to the net capacity at the actual radius.

Question 39Digger Derrick Components, Terminology, and Load Charts

What does the term 'structural capacity' refer to on a digger derrick rating?

  1. The load at which the outriggers sink into the soil
  2. The load that causes the carrier to tip
  3. The maximum load the winch rope can hold
  4. The load the boom, pins, and cylinders can support without damage Correct answer.

Explanation

Structural capacity is limited by the strength of the boom, pins, cylinders, and other machine components. It is distinct from stability, which is governed by tipping, and the chart capacity is the lower of the two limits.

Question 40Digger Derrick Components, Terminology, and Load Charts

Which factor most directly reduces the allowable capacity of a digger derrick when lifting over the side versus over the front?

  1. Side lifts use a longer load line
  2. Side lifts always use a larger hook
  3. Side lifts have a shorter effective counterweight moment and a narrower stability base Correct answer.
  4. Side lifts require a lower hydraulic pressure

Explanation

Crane stability varies with swing position because the carrier's support base and counterweight geometry differ front to back and side to side. Charts provide separate ratings by area, and the side rating is often lower.

Question 41Digger Derrick Components, Terminology, and Load Charts

What is the purpose of the boom holding valve or counterbalance valve on a digger derrick?

  1. To lock the auger in the hole during drilling
  2. To increase the boom's lifting speed under load
  3. To limit the maximum swing angle of the turntable
  4. To prevent the boom from drifting or falling if hydraulic pressure is lost Correct answer.

Explanation

Holding valves trap hydraulic fluid to keep the boom and load from drifting down if a hose fails or the engine stops. They are a safety device and are not intended to control speed or swing.

Question 42Digger Derrick Components, Terminology, and Load Charts

What does the term 'gross capacity' mean on a digger derrick load chart?

  1. The capacity remaining after deducting the hook and rigging
  2. The capacity available only with the boom fully retracted
  3. The total load the derrick can lift before any deductions are applied Correct answer.
  4. The weight of the machine including counterweight

Explanation

Gross capacity is the chart value before deductions for load-handling devices. The operator subtracts the weight of the hook, rigging, and any other required deductions to find the net capacity available for the payload.

Question 43Digger Derrick Components, Terminology, and Load Charts

An operator must set a pole at a 30-foot radius, but the chart shows no rating beyond 25 feet at the required boom length. What is the correct action?

  1. Add counterweight to the rear of the carrier
  2. Proceed slowly because the load is light
  3. Reposition the unit or use a different lifting method within rated capacity Correct answer.
  4. Reduce hydraulic pressure to increase capacity

Explanation

If the required radius or configuration is outside the chart, the lift is not rated and must not be made. The operator repositions the machine or chooses another approved method that falls within the chart.

Question 44Digger Derrick Components, Terminology, and Load Charts

What is the function of the digger derrick's rotation or swing drive?

  1. To operate the outrigger beams
  2. To raise the boom
  3. To extend the boom sections
  4. To rotate the turntable and position the boom around the carrier Correct answer.

Explanation

The swing drive rotates the turntable so the boom can be positioned around the carrier. It is separate from the boom lift, extension, and outrigger systems.

Question 45Digger Derrick Components, Terminology, and Load Charts

Why must the load line be kept vertical during a lift?

  1. To increase the line pull on the winch
  2. To reduce the boom angle indicator reading
  3. To keep the radius measurement accurate and avoid side loading the boom Correct answer.
  4. To prevent the auger from turning

Explanation

A vertical load line keeps the actual radius equal to the measured radius and avoids side loads that can damage the boom. Pulling at an angle changes the radius and introduces forces the chart does not account for.

Question 46Digger Derrick Components, Terminology, and Load Charts

What does the term 'boom length' refer to on a digger derrick?

  1. The horizontal distance from the pivot to the load
  2. The vertical height of the boom tip above the ground
  3. The length of the load line from sheave to hook
  4. The distance from the boom pivot to the boom tip along the boom Correct answer.

Explanation

Boom length is measured along the boom from the pivot point to the tip. It differs from radius, which is horizontal, and from tip height, which is vertical.

Question 47Digger Derrick Components, Terminology, and Load Charts

A digger derrick capacity chart lists a capacity with the boom at 0 degrees. What does this configuration typically represent?

  1. Boom fully raised and retracted
  2. Boom pointing straight down into the hole
  3. Boom stowed for travel
  4. Boom horizontal, which produces the maximum radius for that boom length Correct answer.

Explanation

Zero boom angle means the boom is horizontal, which places the tip at the greatest horizontal distance for a given boom length. Capacities at low angles are correspondingly reduced.

Question 48Digger Derrick Components, Terminology, and Load Charts

What is the purpose of the boom angle indicator on a digger derrick?

  1. To display hydraulic oil temperature
  2. To show the operator the boom angle for entering the capacity chart Correct answer.
  3. To indicate the outrigger extension length
  4. To measure the load weight on the hook

Explanation

The boom angle indicator gives the operator the angle needed to select the correct chart row. It does not measure load or hydraulic conditions.

Question 49Digger Derrick Components, Terminology, and Load Charts

Which practice best ensures the load chart capacity is valid during a lift?

  1. Keeping the boom fully retracted at all times
  2. Lowering the load line speed to the minimum
  3. Using the highest chart capacity regardless of configuration
  4. Keeping outriggers fully extended and set on stable ground Correct answer.

Explanation

Chart capacities assume the machine is set up as specified, including fully extended outriggers on stable, level ground. If setup conditions differ, the listed capacity no longer applies.

Question 50Digger Derrick Components, Terminology, and Load Charts

A digger derrick has a rated capacity of 10,000 pounds at a 12-foot radius. The load, rigging, and hook together weigh 10,000 pounds. What is the status of the lift?

  1. It is within capacity with no margin Correct answer.
  2. It exceeds capacity by the rigging weight
  3. It is acceptable because the hook weight is excluded
  4. It requires the boom to be extended further

Explanation

When the total load equals the rated capacity at the actual radius, the lift is at the limit with no margin for dynamic forces or ground settlement. Best practice is to stay below the limit and account for all weight.