NCCCO Mobile Crane Operator 4 2

Question 1

What is the primary operational difference between an all-terrain mobile crane and a rough terrain crane?

Accepted Answer

All-terrain cranes are designed for highway travel and off-road operation with multi-axle steering, while rough terrain cranes have dedicated two-axle carriers for off-road use

Answer

All-terrain cranes are always larger than rough terrain cranes

Answer

Rough terrain cranes can carry heavier loads due to their lower center of gravity

Answer

All-terrain cranes cannot use outriggers

Question 2

When operating a telescoping boom mobile crane, what is the relationship between boom extension and rated capacity?

Accepted Answer

Rated capacity decreases as the boom is extended due to increased radius and reduced structural efficiency

Answer

Fully extended boom provides maximum rated capacity

Answer

Boom extension has no effect on rated capacity if the load remains within the working radius

Answer

Partially extended booms have lower capacity than either fully retracted or fully extended

Question 3

What is the purpose of the load moment indicator's (LMI) audible pre-warning alert?

Accepted Answer

To alert the operator that the crane is approaching rated capacity, typically at 90%, allowing corrective action before the limit is reached

Answer

To signal the end of the work shift

Answer

To warn nearby workers that a lift is about to begin

Answer

To indicate that the boom angle is below the minimum recommended angle

Question 4

What is a 'duty cycle' lift and how does it differ from standard crane operation?

Accepted Answer

Duty cycle lifting involves repetitive pick-and-carry or clamshell operations where the crane repeatedly lifts and swings loads in a continuous cycle

Answer

Duty cycle lifting uses lighter loads than standard crane operations

Answer

Duty cycle lifting requires a larger crane than specified in the load chart

Answer

Duty cycle lifting only applies to tower cranes, not mobile cranes

Question 5

What is the minimum safe clearance required between a crane's rotating superstructure and adjacent structures during operation?

Accepted Answer

A minimum 2-foot clearance (or manufacturer's specification) must be maintained to prevent pinch point crushing hazards

Answer

No minimum clearance is required if ground spotters are present

Answer

Only 6 inches is required in confined job sites with spotters

Answer

Clearance requirements only apply to the front of the crane, not the rear swing arc

Question 6

What is the purpose of the boom hoist limiting device on a mobile crane?

Accepted Answer

To prevent the boom from being raised above the maximum allowable angle or into a two-blocked position

Answer

To limit the height the main block can travel

Answer

To control the maximum speed of boom hoisting

Answer

To engage the boom locking pins during transport