NCCCO - National Commission for the Certification of Crane Operators Mobile Crane Operator Test 1

Question 1

When setting up a mobile crane on outriggers, what must the operator verify before beginning any lift?

Accepted Answer

The outrigger floats are fully extended and bearing on ground of adequate capacity, with the crane level within manufacturer tolerances

Answer

Outrigger floats must be fully extended (unless the load chart specifies a partial-extension configuration) and the ground must be capable of bearing the imposed load. The crane must also be level within the manufacturer's specified tolerance — typically ±1% — because load charts are based on level operation.

Question 2

A mobile crane's load chart lists capacities based on different boom lengths and radii. What is the 'radius' as used in crane load charts?

Accepted Answer

The horizontal distance from the center of rotation to the center of the load

Answer

Radius is the horizontal distance from the crane's center of rotation (centerline of the turntable) to the center of the suspended load. As radius increases, rated capacity decreases due to the increased overturning moment.

Question 3

What action should a mobile crane operator take if a load starts to swing uncontrollably during a pick?

Accepted Answer

Lower the load as smoothly and quickly as possible to a safe location

Answer

When a load swings uncontrollably, the safest immediate response is to lower it to a stable surface. Attempting to counter-rotate or extending the boom can worsen the dynamic loading and risk tipping the crane.

Question 4

Under OSHA 1926 Subpart CC, who is responsible for ensuring that the weight of the load to be lifted is known before the lift begins?

Accepted Answer

The employer, though the operator may also refuse the lift if the weight is unknown

Answer

OSHA 1926.1412 and 1926.1416 place the duty on the employer to provide the operator with the load weight. The operator has the authority and responsibility to refuse a lift if the weight is unknown or if conditions are unsafe.

Question 5

What does 'structural competency' of a mobile crane refer to?

Accepted Answer

The crane's ability to handle a load without any component failing due to stress

Answer

Structural competency means the crane's structural members — boom, jib, and frame — can withstand the stresses imposed by the load without failing. Load charts account for both tipping (stability) limits and structural limits; the governing limit is the lower of the two.

NCCCO (National Commission for the Certification of Crane Operators) Practice Test

NCCCO (National Commission for the Certification of Crane Operators) Practice Test

NCCCO - National Commission for the Certification of Crane Operators Mobile Crane Operator Test 1