NCCCO Telescoping Boom and Jib Configuration

Question 1

Before extending a telescoping boom section, the operator must first ensure the boom is:

Accepted Answer

Free of any suspended load

Answer

Telescoping a boom under load is prohibited unless the manufacturer's documentation specifically permits it, because the load moment changes as the radius increases.

Question 2

When a mobile crane's telescoping boom is extended to a longer length, the rated lifting capacity will:

Accepted Answer

Decrease as the increased radius increases the load moment

Answer

Extending the boom increases the working radius, and since load moment equals load multiplied by radius, the rated capacity decreases to stay within structural limits.

Question 3

The fly jib 'offset angle' on a mobile crane refers to:

Accepted Answer

The angle between the jib and the main boom centerline

Answer

Offset angle is the angle formed between the centerline of the jib and the centerline of the main boom, and separate load charts exist for each rated offset angle.

Question 4

What is the primary purpose of a fly jib (boom extension) on a mobile crane?

Accepted Answer

To extend the crane's reach in height or radius beyond the main boom

Answer

A fly jib adds length beyond the main boom tip, allowing the crane to reach greater heights or radii that the main boom alone cannot achieve.

Question 5

When using a jib attachment, which load chart must the operator reference?

Accepted Answer

The jib-specific chart for the exact jib length and offset angle being used

Answer

Each jib length and offset angle combination has its own rated capacities; using any other chart would result in an unsafe or incorrect capacity determination.

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

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

NCCCO Telescoping Boom and Jib Configuration