Red Seal Mobile Crane Operator Practice Exam

What does the term "stability triangle" refer to in crane operation?

1. The triangle formed by the load and the hook

2. An area defined by the crane's outriggers that indicates stability under load

3. A safety area for personnel during lifting

4. The operational range of the crane's boom

The correct answer is: An area defined by the crane's outriggers that indicates stability under load

The term "stability triangle" in crane operation refers to an area defined by the crane's outriggers that indicates stability under load. This concept is essential for ensuring the crane remains stable while lifting, especially when dealing with heavy loads or when extending the boom over distances. When the outriggers are properly deployed, they create a triangular area on the ground that signifies a stable base for the crane. It is crucial that the center of gravity of the crane and the load falls within this triangle during operation to prevent tipping or losing control. Understanding the stability triangle helps operators assess the safe lifting capabilities of the crane in various configurations and to identify when additional measures, like using counterweights or extending outriggers, are necessary for safe operations. The other options, while related to crane operation, do not accurately describe the stability triangle. The first option speaks to the relationship between the load and the hook, which is more about load dynamics than stability. The third option refers to safety protocols for personnel, not the crane's stability. The fourth option discusses the operational range of the boom, which relates to how far and high a crane can lift but does not define stability.