NCCO MOBILE CRANE EXAM ACTUAL EXAM 300
QUESTIONS AND ACCURATE DETAILED
ANSWERS
1. A mobile crane's rated capacity is determined by:
A) The operator's certification level
B) The lesser of structural strength and stability
C) The engine horsepower
D) The tire pressure
Correct answer: B) The lesser of structural strength and stability ✅
Rationale: Rated capacity is the lower value between what the structure can withstand
and what will prevent tipping.
2. When using a crane with outriggers, the crane's stability is greatest when the load is
lifted over the:
A) Side
B) Corner
C) Front (over the cab)
D) Rear (over the counterweight)
Correct answer: D) Rear (over the counterweight) ✅
Rationale: Lifting over the rear places the load moment opposite the counterweight,
maximizing stability.
3. A crane's load chart shows a capacity of 22,000 lbs at a 25 ft radius. The hook block
weighs 600 lbs and the slings weigh 150 lbs. What is the maximum load that can be
lifted?
A) 22,000 lbs
B) 21,400 lbs
C) 21,250 lbs
D) 21,850 lbs
Correct answer: C) 21,250 lbs ✅
Rationale: *Net capacity = 22,000 – (600+150) = 21,250 lbs. The load itself must not
exceed this.*
4. The purpose of a crane's outrigger beam stop is to:
A) Prevent over-extension of the beam
B) Lock the beam in place
C) Measure beam extension
,D) Increase hydraulic pressure
Correct answer: A) Prevent over-extension of the beam ✅
Rationale: Mechanical stops prevent the outrigger beam from sliding out beyond its safe
limit.
5. When a crane is operating on rubber (tires), the load chart capacity is typically
reduced because:
A) Tires can puncture
B) The suspension allows the crane to tilt
C) The outriggers are not used
D) The boom is weaker
Correct answer: B) The suspension allows the crane to tilt ✅
Rationale: Tire suspension compliance and smaller stability base reduce capacity
compared to rigid outriggers.
6. A crane's load moment indicator (LMI) must be tested:
A) Monthly
B) At the beginning of each shift
C) Annually
D) Only after repairs
Correct answer: B) At the beginning of each shift ✅
Rationale: Pre-shift functional testing ensures the LMI is working before any lifts.
7. The maximum allowable difference between the actual radius and the radius used for
load chart lookup is:
A) 1 ft
B) 2 ft
C) None; must use exact radius or interpolate
D) 5% of radius
Correct answer: C) None; must use exact radius or interpolate ✅
Rationale: Load charts are specific; using a smaller radius than actual overloads the
crane. Interpolation is allowed only if manufacturer permits.
8. A crane's boom angle indicator reads 50° from horizontal. The radius is 40 ft. What is
the approximate boom length?
A) 52 ft
B) 62 ft
C) 70 ft
D) 80 ft
Correct answer: B) 62 ft ✅
Rationale: *Boom length = radius / cos(angle) = 40 / cos50° = .6428 = 62.2 ft.*
,9. When a crane is set up on a slope, the operator should:
A) Use the standard load chart without change
B) Reduce capacity according to manufacturer's slope chart
C) Increase outrigger pressure
D) Only lift over the uphill side
Correct answer: B) Reduce capacity according to manufacturer's slope chart ✅
Rationale: Slope reduces stability; many manufacturers provide specific reduction factors
or require leveling.
10. The hand signal for "raise the boom and hoist the load simultaneously" is:
A) Two separate signals given alternately
B) A combination signal using one hand for boom and one for hoist
C) Not allowed; only one motion at a time
D) Both arms raised with fists
Correct answer: B) A combination signal using one hand for boom and one for
hoist ✅
Rationale: ASME B30.2 permits combination signals with one hand for each function.
11. A crane's wire rope has a diameter of 1 inch. After wear, it measures 0.94 inches. The
percentage reduction is:
A) 4%
B) 5%
C) 6%
D) 7%
Correct answer: C) 6% ✅
Rationale: *(1.00 - 0.94)/1.00 = 0.06 = 6%, exceeding the 5% limit, so rope must be
replaced.*
12. When using a crane in a tandem lift with two cranes of unequal capacity, the
maximum load should not exceed:
A) The sum of both crane's rated capacities
B) Twice the smaller crane's capacity
C) 75% of the smaller crane's capacity plus 75% of the larger crane's capacity
D) The smaller crane's full capacity
Correct answer: C) 75% of the smaller crane's capacity plus 75% of the larger
crane's capacity ✅
Rationale: Each crane's share is limited to 75% of its individual capacity in tandem lifts.
13. A crane's hoist drum has a flange that is bent outward. The operator should:
A) Continue use but inspect weekly
B) Remove the crane from service until repaired
, C) Reduce line speed
D) Lubricate the flange
Correct answer: B) Remove the crane from service until repaired ✅
Rationale: Bent flanges can allow rope to slip off the drum, causing loss of load.
14. The minimum distance from a crane's swing radius to a building is:
A) 2 ft
B) 5 ft
C) 10 ft
D) As close as possible if barricaded
Correct answer: D) As close as possible if barricaded ✅
Rationale: There is no fixed distance, but the area must be barricaded to prevent
personnel entry; equipment clearance must avoid collision.
15. A crane's anti-two-block device should activate when the hook block is within what
distance of the boom tip?
A) 1 ft
B) 2 ft
C) Manufacturer's specified distance (typically 6-12 inches)
D) 3 ft
Correct answer: C) Manufacturer's specified distance (typically 6-12 inches) ✅
Rationale: The set point varies by crane; it must prevent contact before two-blocking
occurs.
16. When a crane is lifting a load with a 4-leg sling and one leg is slack, the load is
effectively supported by:
A) 4 legs
B) 3 legs
C) 2 legs
D) 1 leg
Correct answer: B) 3 legs ✅
Rationale: A slack leg does not share load; the remaining legs carry the load, potentially
overloading them.
17. A crane's load chart for a specific configuration shows a capacity of 35,000 lbs at 20
ft radius. The operator measures the radius at 21 ft due to boom deflection. The actual
capacity is:
A) 35,000 lbs
B) Less than 35,000 lbs
C) More than 35,000 lbs
D) Unchanged because deflection is normal
QUESTIONS AND ACCURATE DETAILED
ANSWERS
1. A mobile crane's rated capacity is determined by:
A) The operator's certification level
B) The lesser of structural strength and stability
C) The engine horsepower
D) The tire pressure
Correct answer: B) The lesser of structural strength and stability ✅
Rationale: Rated capacity is the lower value between what the structure can withstand
and what will prevent tipping.
2. When using a crane with outriggers, the crane's stability is greatest when the load is
lifted over the:
A) Side
B) Corner
C) Front (over the cab)
D) Rear (over the counterweight)
Correct answer: D) Rear (over the counterweight) ✅
Rationale: Lifting over the rear places the load moment opposite the counterweight,
maximizing stability.
3. A crane's load chart shows a capacity of 22,000 lbs at a 25 ft radius. The hook block
weighs 600 lbs and the slings weigh 150 lbs. What is the maximum load that can be
lifted?
A) 22,000 lbs
B) 21,400 lbs
C) 21,250 lbs
D) 21,850 lbs
Correct answer: C) 21,250 lbs ✅
Rationale: *Net capacity = 22,000 – (600+150) = 21,250 lbs. The load itself must not
exceed this.*
4. The purpose of a crane's outrigger beam stop is to:
A) Prevent over-extension of the beam
B) Lock the beam in place
C) Measure beam extension
,D) Increase hydraulic pressure
Correct answer: A) Prevent over-extension of the beam ✅
Rationale: Mechanical stops prevent the outrigger beam from sliding out beyond its safe
limit.
5. When a crane is operating on rubber (tires), the load chart capacity is typically
reduced because:
A) Tires can puncture
B) The suspension allows the crane to tilt
C) The outriggers are not used
D) The boom is weaker
Correct answer: B) The suspension allows the crane to tilt ✅
Rationale: Tire suspension compliance and smaller stability base reduce capacity
compared to rigid outriggers.
6. A crane's load moment indicator (LMI) must be tested:
A) Monthly
B) At the beginning of each shift
C) Annually
D) Only after repairs
Correct answer: B) At the beginning of each shift ✅
Rationale: Pre-shift functional testing ensures the LMI is working before any lifts.
7. The maximum allowable difference between the actual radius and the radius used for
load chart lookup is:
A) 1 ft
B) 2 ft
C) None; must use exact radius or interpolate
D) 5% of radius
Correct answer: C) None; must use exact radius or interpolate ✅
Rationale: Load charts are specific; using a smaller radius than actual overloads the
crane. Interpolation is allowed only if manufacturer permits.
8. A crane's boom angle indicator reads 50° from horizontal. The radius is 40 ft. What is
the approximate boom length?
A) 52 ft
B) 62 ft
C) 70 ft
D) 80 ft
Correct answer: B) 62 ft ✅
Rationale: *Boom length = radius / cos(angle) = 40 / cos50° = .6428 = 62.2 ft.*
,9. When a crane is set up on a slope, the operator should:
A) Use the standard load chart without change
B) Reduce capacity according to manufacturer's slope chart
C) Increase outrigger pressure
D) Only lift over the uphill side
Correct answer: B) Reduce capacity according to manufacturer's slope chart ✅
Rationale: Slope reduces stability; many manufacturers provide specific reduction factors
or require leveling.
10. The hand signal for "raise the boom and hoist the load simultaneously" is:
A) Two separate signals given alternately
B) A combination signal using one hand for boom and one for hoist
C) Not allowed; only one motion at a time
D) Both arms raised with fists
Correct answer: B) A combination signal using one hand for boom and one for
hoist ✅
Rationale: ASME B30.2 permits combination signals with one hand for each function.
11. A crane's wire rope has a diameter of 1 inch. After wear, it measures 0.94 inches. The
percentage reduction is:
A) 4%
B) 5%
C) 6%
D) 7%
Correct answer: C) 6% ✅
Rationale: *(1.00 - 0.94)/1.00 = 0.06 = 6%, exceeding the 5% limit, so rope must be
replaced.*
12. When using a crane in a tandem lift with two cranes of unequal capacity, the
maximum load should not exceed:
A) The sum of both crane's rated capacities
B) Twice the smaller crane's capacity
C) 75% of the smaller crane's capacity plus 75% of the larger crane's capacity
D) The smaller crane's full capacity
Correct answer: C) 75% of the smaller crane's capacity plus 75% of the larger
crane's capacity ✅
Rationale: Each crane's share is limited to 75% of its individual capacity in tandem lifts.
13. A crane's hoist drum has a flange that is bent outward. The operator should:
A) Continue use but inspect weekly
B) Remove the crane from service until repaired
, C) Reduce line speed
D) Lubricate the flange
Correct answer: B) Remove the crane from service until repaired ✅
Rationale: Bent flanges can allow rope to slip off the drum, causing loss of load.
14. The minimum distance from a crane's swing radius to a building is:
A) 2 ft
B) 5 ft
C) 10 ft
D) As close as possible if barricaded
Correct answer: D) As close as possible if barricaded ✅
Rationale: There is no fixed distance, but the area must be barricaded to prevent
personnel entry; equipment clearance must avoid collision.
15. A crane's anti-two-block device should activate when the hook block is within what
distance of the boom tip?
A) 1 ft
B) 2 ft
C) Manufacturer's specified distance (typically 6-12 inches)
D) 3 ft
Correct answer: C) Manufacturer's specified distance (typically 6-12 inches) ✅
Rationale: The set point varies by crane; it must prevent contact before two-blocking
occurs.
16. When a crane is lifting a load with a 4-leg sling and one leg is slack, the load is
effectively supported by:
A) 4 legs
B) 3 legs
C) 2 legs
D) 1 leg
Correct answer: B) 3 legs ✅
Rationale: A slack leg does not share load; the remaining legs carry the load, potentially
overloading them.
17. A crane's load chart for a specific configuration shows a capacity of 35,000 lbs at 20
ft radius. The operator measures the radius at 21 ft due to boom deflection. The actual
capacity is:
A) 35,000 lbs
B) Less than 35,000 lbs
C) More than 35,000 lbs
D) Unchanged because deflection is normal
