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

When removing pins or bolts from a boom assembly, workers shall remain:

1. Clear of sledge hammers

2. Out from under the boom

3. On top of boom holding pendants

4. In sight of the operator

The correct answer is: Out from under the boom

Remaining out from under the boom when removing pins or bolts from a boom assembly is imperative for safety reasons. The boom is a heavy component of the crane, and if any part were to fall or become improperly supported during maintenance, it could lead to serious injury or fatality. By staying clear of the area directly underneath the boom, workers minimize the risk of being struck by falling equipment or components. In contrast, being clear of sledge hammers, holding pendants on top of the boom, or being in sight of the operator does not provide the same critical level of protection against potential hazards associated with boom assembly maintenance. While those actions are also considered in a safe work environment, the primary concern when working with heavy machinery like cranes is to ensure that personnel are not exposed to falling objects from above.