Telescoping Boom and Jib Configuration Flashcards
7 cards from real NCCCO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Telescoping Boom and Jib Configuration flashcards as text
When a telescoping boom section is positioned at an intermediate (mid-travel) extension — not fully extended or retracted — the operator should:
Answer: Consult the manufacturer's manual, as intermediate positions may not be load-rated
Many manufacturers only rate capacities at specific fully-extended or fully-retracted boom positions; intermediate positions may lack structural pin engagement and are often not rated for lifting.
Which type of jib attachment allows the operator to adjust the jib angle while the crane is under load during operations?
Answer: Luffing jib
A luffing jib has its own luffing mechanism that allows the operator to raise or lower the jib tip while a load is suspended, unlike fixed or swingaway jibs which must be pinned before the lift.
When is it generally permissible to telescope a hydraulic boom while a load is suspended from the hook?
Answer: Only when the manufacturer's documentation specifically permits power telescoping under load
Some cranes are designed for power telescoping under load, but this must be explicitly permitted and detailed in the manufacturer's documentation, as capacity changes dynamically.
When the telescoping boom is extended, the crane's center of gravity shifts in which direction?
Answer: Toward the front of the crane, reducing tipping stability
Extending the boom moves mass forward and outward, shifting the crane's center of gravity toward the load side and reducing the margin against tipping.
After completing operations, a swingaway jib should be:
Answer: Secured alongside the main boom in the travel position per manufacturer instructions
The manufacturer specifies an approved travel/stow position for the swingaway jib to prevent damage during transport and maintain safe travel dimensions.
A luffing jib differs from a fixed jib primarily because it:
Answer: Can be raised and lowered during crane operation without changing pins
A luffing jib uses its own hydraulic or wire rope luffing system to change the jib angle dynamically during a pick, providing precise placement capability in congested areas.
When a jib attachment changes the crane's operating configuration, the operator must:
Answer: Reference the load chart specific to the new jib configuration
Each crane configuration — boom-only, boom plus jib, different jib lengths and offset angles — has its own load chart, and using the wrong chart results in unsafe load determinations.