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

Which hand signal is to be obeyed at all times during crane operations?

1. Go

2. Slow Down

3. Stop

4. Lift

The correct answer is: Stop

The hand signal for "Stop" is crucial during crane operations because it represents an immediate action that must be taken to ensure safety. When this signal is given, all movement must cease instantly, regardless of the ongoing operation. This is essential for preventing accidents and injuries, as it serves as a universal command that indicates a need to halt operations due to various potential hazards that may arise, such as sudden changes in load stability or the presence of personnel in danger. While other signals like "Go," "Slow Down," or "Lift" play important roles during crane operations, they do not carry the same level of urgency or importance as the "Stop" signal. In high-risk environments where heavy machinery is involved, the ability to instantly stop operations can save lives and prevent damage, making it a fundamental rule to obey this signal at all times.