MASS Load Charts and Capacity 3 — Questions and Answers
Question 1: When calculating load radius, the measurement is taken from the center of rotation to:
- The center of the suspended load (Correct answer)
- The tip of the boom only
- The rear of the carrier
- The operator's seat
Correct answer: The center of the suspended load
Load radius is the horizontal distance from the center of rotation to the vertical centerline of the load.
Question 2: Boom deflection under load tends to do what to the actual operating radius?
- Increase it beyond the no-load radius (Correct answer)
- Decrease it
- Eliminate it
- Have no effect
Correct answer: Increase it beyond the no-load radius
As the boom bends under load it moves the tip outward, increasing the real radius and lowering capacity.
Question 3: If a load chart lists capacities for 'fully extended outriggers,' using mid-extended outriggers means you must:
- Use the lower mid-extended capacity column instead (Correct answer)
- Use the same numbers
- Increase the rated capacity
- Ignore the outrigger setting
Correct answer: Use the lower mid-extended capacity column instead
Reduced outrigger spread narrows the stability base, so a separate, lower capacity column applies.
Question 4: A 360-degree (over-the-side) rating compared to an over-the-rear rating on a rough-terrain crane is usually:
- Lower, because over-the-side is the least stable orientation (Correct answer)
- Higher
- Identical in all cases
- Not listed on charts
Correct answer: Lower, because over-the-side is the least stable orientation
Over-the-side lifts are governed by the narrowest stability and therefore carry lower ratings.
Question 5: What information does the 'range diagram' portion of crane documentation provide?
- The relationship between boom length, boom angle, radius, and lift height (Correct answer)
- Only the fuel capacity
- The paint color codes
- Tire replacement schedule
Correct answer: The relationship between boom length, boom angle, radius, and lift height
The range diagram shows how boom length and angle translate into radius and available lifting height.
Question 6: If the planned lift exceeds the chart capacity at the required radius, the correct action is to:
- Stop and reconfigure, use a larger crane, or reduce the load (Correct answer)
- Add operators to the cab
- Increase the engine throttle
- Lift quickly to avoid tipping
Correct answer: Stop and reconfigure, use a larger crane, or reduce the load
Exceeding rated capacity is never permitted; the lift must be replanned with a different setup or machine.
Question 7: The weight of an auxiliary lifting attachment such as a jib that is erected but not in use should be:
- Deducted from the main boom's capacity as required by the chart notes (Correct answer)
- Ignored entirely
- Added to the capacity
- Counted as counterweight
Correct answer: Deducted from the main boom's capacity as required by the chart notes
An erected jib, even when unused, adds weight that reduces main-boom capacity per the chart's deduction notes.
MASS Load Charts and Capacity 3
When calculating load radius, the measurement is taken from the center of rotation to: