NCCCO MOBILE CRANE OPERATOR -
ADVANCED PRACTICE EXAM 4
1. When determining the gross capacity of a crane, which of the following must be subtracted
from the chart capacity to find the net capacity?
A. The weight of the load only
B. The weight of the hook block, rigging, and effective weight of the jib
C. The weight of the boom and the counterweight
D. The weight of the fuel in the crane tanks
Answer: B
Conceptual Explanation: Net capacity is calculated by subtracting all ‘deductions’ (hook
block, ball, slings, shackles, and any stowed or erected jib weight not in use) from the gross
capacity listed in the load chart.
2. According to OSHA 1926.1408, what is the minimum clearance distance for power lines
rated up to 50kV when the voltage is unknown?
A. 20 feet
B. 15 feet
,C. 10 feet
D. 45 feet
Answer: A
Conceptual Explanation: If the voltage is unknown, OSHA requires a 20-foot clearance for
lines up to 350kV, but specifically for lines up to 50kV, Table A specifies 10 feet. However,
the general safety rule for unknown lines up to 350kV is 20 feet to be safe.
3. Which factor has the greatest effect on the loss of crane capacity when the crane is not
level?
A. Side loading of the boom
B. Increased hoist line speed
C. Reduced hydraulic pressure
D. Decreased radius
Answer: A
Conceptual Explanation: Operating a crane out of level creates side loading on the boom,
which can lead to structural failure even if the load is within the chart capacity.
4. A ‘duty cycle’ operation, such as concrete pouring or dragline work, usually requires which
of the following?
A. Increasing the load chart capacity by 10%
B. Reduction in rated capacity per manufacturer’s guidelines
, C. Increasing the swing speed to maximize efficiency
D. Using a shorter boom than specified
Answer: B
Conceptual Explanation: Duty cycle work involves constant movement and dynamic
loading. Manufacturers typically require a reduction (often 20% or more) in the load chart
capacity to account for these stresses.
5. When using a lattice boom crane, what is the primary indicator of an impending stability
failure?
A. The boom begins to twist
B. The crane’s tracks or outriggers begin to lift off the ground
C. The hoist line begins to fray
D. The engine RPMs drop significantly
Answer: B
Conceptual Explanation: Stability failure (tipping) is physically indicated by the crane’s
base lifting away from the ground on the side opposite the load.
6. What is the result of using a snatch block in the hoist line?
A. It changes the direction of the pull or increases mechanical advantage
B. It increases the crane’s boom length
C. It doubles the line speed
ADVANCED PRACTICE EXAM 4
1. When determining the gross capacity of a crane, which of the following must be subtracted
from the chart capacity to find the net capacity?
A. The weight of the load only
B. The weight of the hook block, rigging, and effective weight of the jib
C. The weight of the boom and the counterweight
D. The weight of the fuel in the crane tanks
Answer: B
Conceptual Explanation: Net capacity is calculated by subtracting all ‘deductions’ (hook
block, ball, slings, shackles, and any stowed or erected jib weight not in use) from the gross
capacity listed in the load chart.
2. According to OSHA 1926.1408, what is the minimum clearance distance for power lines
rated up to 50kV when the voltage is unknown?
A. 20 feet
B. 15 feet
,C. 10 feet
D. 45 feet
Answer: A
Conceptual Explanation: If the voltage is unknown, OSHA requires a 20-foot clearance for
lines up to 350kV, but specifically for lines up to 50kV, Table A specifies 10 feet. However,
the general safety rule for unknown lines up to 350kV is 20 feet to be safe.
3. Which factor has the greatest effect on the loss of crane capacity when the crane is not
level?
A. Side loading of the boom
B. Increased hoist line speed
C. Reduced hydraulic pressure
D. Decreased radius
Answer: A
Conceptual Explanation: Operating a crane out of level creates side loading on the boom,
which can lead to structural failure even if the load is within the chart capacity.
4. A ‘duty cycle’ operation, such as concrete pouring or dragline work, usually requires which
of the following?
A. Increasing the load chart capacity by 10%
B. Reduction in rated capacity per manufacturer’s guidelines
, C. Increasing the swing speed to maximize efficiency
D. Using a shorter boom than specified
Answer: B
Conceptual Explanation: Duty cycle work involves constant movement and dynamic
loading. Manufacturers typically require a reduction (often 20% or more) in the load chart
capacity to account for these stresses.
5. When using a lattice boom crane, what is the primary indicator of an impending stability
failure?
A. The boom begins to twist
B. The crane’s tracks or outriggers begin to lift off the ground
C. The hoist line begins to fray
D. The engine RPMs drop significantly
Answer: B
Conceptual Explanation: Stability failure (tipping) is physically indicated by the crane’s
base lifting away from the ground on the side opposite the load.
6. What is the result of using a snatch block in the hoist line?
A. It changes the direction of the pull or increases mechanical advantage
B. It increases the crane’s boom length
C. It doubles the line speed
