NCCCO Lattice Boom Crane Configuration and Operations

Question 1

What is the primary function of a boom pendant (back hitch) on a lattice boom crane?

Accepted Answer

It suspends and supports the boom from the mast or A-frame, controlling boom angle

Answer

Boom pendants run from the boom tip back to the crane's A-frame or mast, supporting the boom's weight and maintaining its working angle. They are part of the boom suspension system and must be correctly rigged and tensioned before any lifting begins.

Question 2

What distinguishes a luffing jib from a fixed jib on a lattice boom crane?

Accepted Answer

A luffing jib can be raised or lowered independently while the crane is in service

Answer

A luffing jib can be raised and lowered (luffed) independently while the crane is working, allowing the operator to change working radius without repositioning the crane. A fixed jib is set at a fixed offset angle and cannot be adjusted during operations.

Question 3

When assembling boom sections on a lattice boom crane, what must be verified before adding additional sections?

Accepted Answer

All section pins are fully inserted and secured with their retaining devices

Answer

Each boom section must be connected using the correct pins, with all retaining devices (cotter pins, keeper plates, or snap rings) fully installed before the next section is added or the boom is raised. A missing or partially inserted pin can cause catastrophic boom collapse.

Question 4

What is the primary ground-bearing advantage of a crawler crane over a rubber-tired mobile crane?

Accepted Answer

Crawlers distribute the crane's weight over a much larger footprint, reducing ground bearing pressure

Answer

Crawler undercarriages spread the crane's total weight across the full length of both crawler pads, dramatically reducing ground bearing pressure per square foot compared to rubber-tired cranes that concentrate weight on discrete tire contact patches. This makes crawler cranes better suited for soft or uneven terrain.

Question 5

What hazard results from allowing boom suspension pendants to go slack on a lattice boom crane while a load is being handled?

Accepted Answer

Slack pendants remove the boom's rear support, allowing the boom to kick forward suddenly when load is applied, increasing radius uncontrollably

Answer

If boom pendants go slack, the boom loses its rear suspension. When a load is applied, the boom can rotate forward suddenly (boom fallover), dramatically increasing the working radius beyond the load chart value — frequently causing the crane to tip or the boom to buckle.

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

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

NCCCO Lattice Boom Crane Configuration and Operations