NCCCO MOBILE CRANE EXAM/ QUESTIONS
AND ANSWERS (CRANE PRACTICE TESTS)
Questions 1-5: Load Chart & Advanced Capacity Calculations
1. A telescopic crane is set up on fully extended outriggers with a 10,000 lb hook block installed. The
load chart shows the main boom capacity is 45,000 lb at the required radius. The load to be lifted
weighs 32,000 lb, and the rigging (slings and shackles) weighs 800 lb. However, the jib is currently
erected but NOT being used for this lift. According to most manufacturer load chart notes, what is the
net capacity for this lift?
A. 45,000 lb - 10,000 lb (hook block) - 800 lb (rigging) = 34,200 lb
B. 45,000 lb - 10,000 lb - 800 lb - "effective weight" of the unused jib = less than 34,200 lb
C. 45,000 lb - 800 lb (rigging only) = 44,200 lb
D. 45,000 lb - 10,000 lb - "effective weight" of the unused jib = 35,000 lb minus jib deduction
Answer: B
Rationale: This is a common trick question. The net capacity calculation involves subtracting:
1. The weight of the hook block (load handling device)
2. The weight of all rigging (slings, shackles)
3. Most critically, the "effective weight" of any erected jib not in use
The effective weight is often greater than the actual weight of the jib because the jib acts as a lever arm
against the main boom. Even though the jib is not lifting anything, its presence creates additional stress
on the crane structure . Many candidates forget this deduction.
,2. You are consulting a load chart that has a BOLD horizontal line across the capacity columns. What is
the significance of capacities listed BELOW this bold line?
A. These capacities are only valid when operating on outriggers
B. These capacities are based on the structural strength of the crane
C. These capacities are based on the stability of the crane (tipping)
D. These capacities require a 50% reduction for safety
Answer: C
Rationale: The bold line on a load chart separates two distinct limiting factors :
Location on Chart Limiting Factor What This Means
Above the bold Structural The crane will structurally fail (boom buckling, component
line strength fracture) before it tips
Below the bold Stability
The crane will tip over before any structural damage occurs
line (tipping)
Capacities below the bold line are typically calculated at 85% of tipping load for mobile cranes on
outriggers . This is a safety margin—the crane is rated to tip at 100%, but safe working load is set at
85% of that point.
3. A crawler crane has a rated line pull of 8,000 lb per part of line. You need to lift a total gross load
(load + rigging + hook block) of 52,000 lb. Using the standard 75% efficiency factor required for
, crawler crane hoist systems with 4 or more parts of line, what is the MINIMUM number of parts of line
required?
A. 6 parts (52,000 ÷ 8,000 = 6.5 → round up to 7, but with efficiency factor)
B. 7 parts
C. 8 parts
D. 9 parts
Answer: D (9 parts)
Rationale: This problem requires a two-step calculation:
1. Basic parts needed without efficiency: 52,000 lb ÷ 8,000 lb per part = 6.5 parts → round UP to 7
parts (cannot use partial parts)
2. Apply the 75% efficiency factor for crawler cranes with 4+ parts:
o Each line only contributes 75% of its rated capacity when using multiple parts
o Adjusted capacity per part = 8,000 lb × 0.75 = 6,000 lb effective capacity
o 52,000 lb ÷ 6,000 lb = 8.67 parts → round UP to 9 parts
Why the efficiency factor exists: Friction through the multiple sheaves in the hook block and boom tip
reduces the actual lifting capability. As parts of line increase, friction losses accumulate .
4. A load chart shows capacities for the following boom lengths: 50 ft, 60 ft, 70 ft, and 80 ft. Your actual
boom length is 67 ft at the required radius. The capacity at 60 ft is 32,000 lb and at 70 ft is 28,500 lb.
What is the maximum load you can legally lift according to standard NCCCO load chart rules?
A. 30,250 lb (interpolated between 32,000 and 28,500)
B. 32,000 lb (use the next shorter boom length capacity)
C. 28,500 lb (use the next longer boom length capacity)
D. Cannot be determined without manufacturer interpolation approval
Answer: B
AND ANSWERS (CRANE PRACTICE TESTS)
Questions 1-5: Load Chart & Advanced Capacity Calculations
1. A telescopic crane is set up on fully extended outriggers with a 10,000 lb hook block installed. The
load chart shows the main boom capacity is 45,000 lb at the required radius. The load to be lifted
weighs 32,000 lb, and the rigging (slings and shackles) weighs 800 lb. However, the jib is currently
erected but NOT being used for this lift. According to most manufacturer load chart notes, what is the
net capacity for this lift?
A. 45,000 lb - 10,000 lb (hook block) - 800 lb (rigging) = 34,200 lb
B. 45,000 lb - 10,000 lb - 800 lb - "effective weight" of the unused jib = less than 34,200 lb
C. 45,000 lb - 800 lb (rigging only) = 44,200 lb
D. 45,000 lb - 10,000 lb - "effective weight" of the unused jib = 35,000 lb minus jib deduction
Answer: B
Rationale: This is a common trick question. The net capacity calculation involves subtracting:
1. The weight of the hook block (load handling device)
2. The weight of all rigging (slings, shackles)
3. Most critically, the "effective weight" of any erected jib not in use
The effective weight is often greater than the actual weight of the jib because the jib acts as a lever arm
against the main boom. Even though the jib is not lifting anything, its presence creates additional stress
on the crane structure . Many candidates forget this deduction.
,2. You are consulting a load chart that has a BOLD horizontal line across the capacity columns. What is
the significance of capacities listed BELOW this bold line?
A. These capacities are only valid when operating on outriggers
B. These capacities are based on the structural strength of the crane
C. These capacities are based on the stability of the crane (tipping)
D. These capacities require a 50% reduction for safety
Answer: C
Rationale: The bold line on a load chart separates two distinct limiting factors :
Location on Chart Limiting Factor What This Means
Above the bold Structural The crane will structurally fail (boom buckling, component
line strength fracture) before it tips
Below the bold Stability
The crane will tip over before any structural damage occurs
line (tipping)
Capacities below the bold line are typically calculated at 85% of tipping load for mobile cranes on
outriggers . This is a safety margin—the crane is rated to tip at 100%, but safe working load is set at
85% of that point.
3. A crawler crane has a rated line pull of 8,000 lb per part of line. You need to lift a total gross load
(load + rigging + hook block) of 52,000 lb. Using the standard 75% efficiency factor required for
, crawler crane hoist systems with 4 or more parts of line, what is the MINIMUM number of parts of line
required?
A. 6 parts (52,000 ÷ 8,000 = 6.5 → round up to 7, but with efficiency factor)
B. 7 parts
C. 8 parts
D. 9 parts
Answer: D (9 parts)
Rationale: This problem requires a two-step calculation:
1. Basic parts needed without efficiency: 52,000 lb ÷ 8,000 lb per part = 6.5 parts → round UP to 7
parts (cannot use partial parts)
2. Apply the 75% efficiency factor for crawler cranes with 4+ parts:
o Each line only contributes 75% of its rated capacity when using multiple parts
o Adjusted capacity per part = 8,000 lb × 0.75 = 6,000 lb effective capacity
o 52,000 lb ÷ 6,000 lb = 8.67 parts → round UP to 9 parts
Why the efficiency factor exists: Friction through the multiple sheaves in the hook block and boom tip
reduces the actual lifting capability. As parts of line increase, friction losses accumulate .
4. A load chart shows capacities for the following boom lengths: 50 ft, 60 ft, 70 ft, and 80 ft. Your actual
boom length is 67 ft at the required radius. The capacity at 60 ft is 32,000 lb and at 70 ft is 28,500 lb.
What is the maximum load you can legally lift according to standard NCCCO load chart rules?
A. 30,250 lb (interpolated between 32,000 and 28,500)
B. 32,000 lb (use the next shorter boom length capacity)
C. 28,500 lb (use the next longer boom length capacity)
D. Cannot be determined without manufacturer interpolation approval
Answer: B
