NCCCO Digger Derrick Operator Exam
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. What is the primary purpose of a digger derrick on a utility construction site?
A. To transport personnel between work locations
B. To drill holes, lift and position loads, and perform related utility construction
tasks
D. To replace all excavation equipment on a construction site
Answer: B. To drill holes, lift and position loads, and perform related utility
construction tasks
Rationale: A digger derrick is a versatile utility construction machine designed
primarily for drilling holes and handling loads such as poles and equipment. Its
functions must be performed within the manufacturer's operating limits, rated
capacities, and applicable safety requirements.
2. Before operating a digger derrick, what should the operator do first?
A. Immediately extend the boom to test the controls
B. Start drilling to verify the hydraulic system
C. Review the manufacturer's operating instructions and perform the required
inspection
D. Determine the maximum load by lifting a test load
Answer: C. Review the manufacturer's operating instructions and perform the
required inspection
,Rationale: A thorough pre-operation inspection and review of operating instructions
help identify unsafe conditions before the machine is placed into service. The
operator should understand the machine's controls, limitations, capacities,
warnings, and required inspection procedures.
3. Which factor has the greatest direct effect on a digger derrick's lifting
capacity?
A. Paint color
B. Load radius and configuration
C. Operator's years of experience
D. Engine coolant temperature alone
Answer: B. Load radius and configuration
Rationale: Rated capacity depends on factors such as boom configuration,
operating radius, boom angle, load position, machine setup, and manufacturer-
rated limitations. As operating radius increases, available lifting capacity commonly
decreases because of the increased overturning moment.
4. What is the purpose of the load chart on a digger derrick?
A. To identify the machine's fuel consumption
B. To specify allowable lifting capacities under different operating conditions
C. To identify recommended tire pressures only
D. To determine the age of the machine
Answer: B. To specify allowable lifting capacities under different operating
conditions
Rationale: The load chart provides capacity information for specified machine
configurations and conditions. Operators must use the correct chart for the
machine and configuration rather than estimating capacity from experience or
appearance.
5. What should an operator do if the load chart is missing or unreadable?
,A. Estimate capacity from the previous day's work
B. Operate only at maximum boom angle
C. Stop and obtain the correct readable capacity information before making the lift
D. Ask a ground worker to estimate the capacity
Answer: C. Stop and obtain the correct readable capacity information before
making the lift
Rationale: Capacity information is critical to safe operation. If the chart cannot be
read or verified, the operator cannot reliably determine whether a planned lift is
within the machine's rated limits.
6. What is the main purpose of outriggers on a digger derrick?
A. To increase engine speed
B. To stabilize the machine and distribute supporting forces
C. To increase drilling speed
D. To cool the hydraulic oil
Answer: B. To stabilize the machine and distribute supporting forces
Rationale: Outriggers help establish a stable operating platform and transfer
machine forces into the supporting surface. They must be properly deployed and
positioned according to the manufacturer's instructions and site conditions.
7. Why should outrigger pads or suitable blocking be used when required?
A. To increase fuel efficiency
B. To prevent the machine from becoming too cold
C. To distribute outrigger forces over an appropriate supporting area
D. To increase engine horsepower
Answer: C. To distribute outrigger forces over an appropriate supporting area
Rationale: Outrigger reactions can be substantial. Proper pads or blocking help
distribute these forces and reduce the possibility of sinking, punching, shifting, or
destabilizing the machine when the ground cannot safely support concentrated
loads.
, 8. Which ground condition presents a serious stability concern for a digger
derrick?
A. Firm, properly compacted soil
B. Level concrete designed for the equipment
C. Uncompacted fill or soil with inadequate bearing capacity
D. Properly prepared gravel
Answer: C. Uncompacted fill or soil with inadequate bearing capacity
Rationale: Weak, loose, saturated, or poorly compacted ground may deform under
outrigger loads. Ground failure can cause the machine to shift or overturn even
when the lifted load itself is within the rated capacity.
9. What should the operator consider when setting up near an excavation?
A. Only the machine's fuel level
B. The excavation's edge, depth, soil stability, and potential for ground failure
C. Only the color of the soil
D. Only the direction of the wind
Answer: B. The excavation's edge, depth, soil stability, and potential for ground
failure
Rationale: An excavation can reduce the supporting capacity of the ground near its
edge. Outrigger placement and machine loading can contribute to collapse or
overturning if adequate separation and support are not maintained.
10.What is the safest general approach when the supporting surface appears
questionable?
A. Proceed slowly and assume the surface will hold
B. Reduce the load but ignore the ground condition
C. Have the site condition evaluated and establish adequate support before
operating
D. Extend the boom farther to reduce the machine's load
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. What is the primary purpose of a digger derrick on a utility construction site?
A. To transport personnel between work locations
B. To drill holes, lift and position loads, and perform related utility construction
tasks
D. To replace all excavation equipment on a construction site
Answer: B. To drill holes, lift and position loads, and perform related utility
construction tasks
Rationale: A digger derrick is a versatile utility construction machine designed
primarily for drilling holes and handling loads such as poles and equipment. Its
functions must be performed within the manufacturer's operating limits, rated
capacities, and applicable safety requirements.
2. Before operating a digger derrick, what should the operator do first?
A. Immediately extend the boom to test the controls
B. Start drilling to verify the hydraulic system
C. Review the manufacturer's operating instructions and perform the required
inspection
D. Determine the maximum load by lifting a test load
Answer: C. Review the manufacturer's operating instructions and perform the
required inspection
,Rationale: A thorough pre-operation inspection and review of operating instructions
help identify unsafe conditions before the machine is placed into service. The
operator should understand the machine's controls, limitations, capacities,
warnings, and required inspection procedures.
3. Which factor has the greatest direct effect on a digger derrick's lifting
capacity?
A. Paint color
B. Load radius and configuration
C. Operator's years of experience
D. Engine coolant temperature alone
Answer: B. Load radius and configuration
Rationale: Rated capacity depends on factors such as boom configuration,
operating radius, boom angle, load position, machine setup, and manufacturer-
rated limitations. As operating radius increases, available lifting capacity commonly
decreases because of the increased overturning moment.
4. What is the purpose of the load chart on a digger derrick?
A. To identify the machine's fuel consumption
B. To specify allowable lifting capacities under different operating conditions
C. To identify recommended tire pressures only
D. To determine the age of the machine
Answer: B. To specify allowable lifting capacities under different operating
conditions
Rationale: The load chart provides capacity information for specified machine
configurations and conditions. Operators must use the correct chart for the
machine and configuration rather than estimating capacity from experience or
appearance.
5. What should an operator do if the load chart is missing or unreadable?
,A. Estimate capacity from the previous day's work
B. Operate only at maximum boom angle
C. Stop and obtain the correct readable capacity information before making the lift
D. Ask a ground worker to estimate the capacity
Answer: C. Stop and obtain the correct readable capacity information before
making the lift
Rationale: Capacity information is critical to safe operation. If the chart cannot be
read or verified, the operator cannot reliably determine whether a planned lift is
within the machine's rated limits.
6. What is the main purpose of outriggers on a digger derrick?
A. To increase engine speed
B. To stabilize the machine and distribute supporting forces
C. To increase drilling speed
D. To cool the hydraulic oil
Answer: B. To stabilize the machine and distribute supporting forces
Rationale: Outriggers help establish a stable operating platform and transfer
machine forces into the supporting surface. They must be properly deployed and
positioned according to the manufacturer's instructions and site conditions.
7. Why should outrigger pads or suitable blocking be used when required?
A. To increase fuel efficiency
B. To prevent the machine from becoming too cold
C. To distribute outrigger forces over an appropriate supporting area
D. To increase engine horsepower
Answer: C. To distribute outrigger forces over an appropriate supporting area
Rationale: Outrigger reactions can be substantial. Proper pads or blocking help
distribute these forces and reduce the possibility of sinking, punching, shifting, or
destabilizing the machine when the ground cannot safely support concentrated
loads.
, 8. Which ground condition presents a serious stability concern for a digger
derrick?
A. Firm, properly compacted soil
B. Level concrete designed for the equipment
C. Uncompacted fill or soil with inadequate bearing capacity
D. Properly prepared gravel
Answer: C. Uncompacted fill or soil with inadequate bearing capacity
Rationale: Weak, loose, saturated, or poorly compacted ground may deform under
outrigger loads. Ground failure can cause the machine to shift or overturn even
when the lifted load itself is within the rated capacity.
9. What should the operator consider when setting up near an excavation?
A. Only the machine's fuel level
B. The excavation's edge, depth, soil stability, and potential for ground failure
C. Only the color of the soil
D. Only the direction of the wind
Answer: B. The excavation's edge, depth, soil stability, and potential for ground
failure
Rationale: An excavation can reduce the supporting capacity of the ground near its
edge. Outrigger placement and machine loading can contribute to collapse or
overturning if adequate separation and support are not maintained.
10.What is the safest general approach when the supporting surface appears
questionable?
A. Proceed slowly and assume the surface will hold
B. Reduce the load but ignore the ground condition
C. Have the site condition evaluated and establish adequate support before
operating
D. Extend the boom farther to reduce the machine's load
