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

What may happen to a long boom crane at a short radius if it is out of level by 300?

1. It may not lift any weight

2. It can see a reduction in capacity by as much as 50%

3. It will function normally without any changes

4. It will increase capacity significantly

The correct answer is: It can see a reduction in capacity by as much as 50%

A long boom crane that is out of level by 3 degrees can indeed experience a significant reduction in its lifting capacity, which aligns with the correct choice indicating a potential reduction by as much as 50%. When a crane is not level, it affects the distribution of weight and the stability of the crane, particularly at short radii where the center of gravity is more critical. At a short radius, the leverage applied to the crane's structure can become unbalanced if the boom is tilted even slightly, leading to greater stress on one side of the crane. This imbalance can reduce the operational capacity considerably due to the increased risk of tipping over or exceeding stability limits. In addition, crane manufacturers provide load charts that specify lifting capacities based on the crane’s configuration, including its levelness. A 3-degree tilt, although seemingly small, can fall outside of these safe operational conditions, further contributing to the capacity reduction. Maintaining a level position is essential for ensuring safe and effective lifting operations, particularly with long boom cranes that are sensitive to changes in angle and load distribution.