NCCCO Telescoping Boom and Jib Configuration 2 — Questions and Answers
Question 1: When a telescoping boom section is positioned at an intermediate (mid-travel) extension — not fully extended or retracted — the operator should:
- Continue the lift but reduce the load by 25%
- Consult the manufacturer's manual, as intermediate positions may not be load-rated (Correct answer)
- Always extend fully before attempting any lift
- Always retract fully before attempting any lift
Correct 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.
Question 2: Which type of jib attachment allows the operator to adjust the jib angle while the crane is under load during operations?
- Fixed jib
- Swingaway jib
- Luffing jib (Correct answer)
- Lattice extension
Correct 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.
Question 3: When is it generally permissible to telescope a hydraulic boom while a load is suspended from the hook?
- Always, provided the operator moves slowly and smoothly
- Only when the load is below 50% of rated capacity
- Never under any circumstances
- Only when the manufacturer's documentation specifically permits power telescoping under load (Correct answer)
Correct 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.
Question 4: When the telescoping boom is extended, the crane's center of gravity shifts in which direction?
- Toward the front of the crane, reducing tipping stability (Correct answer)
- Upward only, with no horizontal effect on stability
- Toward the rear of the crane, increasing stability
- It does not change unless the counterweight is adjusted
Correct 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.
Question 5: After completing operations, a swingaway jib should be:
- Left hanging from the boom tip for faster redeployment
- Secured alongside the main boom in the travel position per manufacturer instructions (Correct answer)
- Fully detached and stored separately in a tool crib
- Lowered to the ground and left rigged for the next shift
Correct 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.
Question 6: A luffing jib differs from a fixed jib primarily because it:
- Is constructed from lattice sections rather than box sections
- Can be raised and lowered during crane operation without changing pins (Correct answer)
- Does not require separate capacity load charts
- Attaches at the boom base rather than the boom tip
Correct 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.
Question 7: When a jib attachment changes the crane's operating configuration, the operator must:
- Notify the equipment owner by written report before the lift
- Recalculate all loads using the original main boom-only chart
- Reference the load chart specific to the new jib configuration (Correct answer)
- Reduce all lifts to 50% of rated capacity until recertified
Correct 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.
NCCCO Telescoping Boom and Jib Configuration 2
When a telescoping boom section is positioned at an intermediate (mid-travel) extension — not fully extended or retracted — the operator should: