What is prohibited while the engine is running on a crane?

Leaving the operator's cab with the load suspended on a crane is prohibited while the engine is running because it poses a significant safety hazard. When a load is suspended, it can drop unexpectedly if the controls are inadvertently engaged or if there is a mechanical failure. The operator must maintain control over the load to ensure that it does not pose a risk to themselves or others in the vicinity. The operator's cab is designed as a secure area for the operator to remain vigilant and focused on the load and surrounding environment. Therefore, it is vital to avoid any situations where the operator is not present at the controls with a load in the air, which could lead to accidents or injuries.

The choices related to performing maintenance, adjusting the boom angle, and using emergency stop functions all involve scenarios that are typically addressed in operational protocols to ensure safety. Performing maintenance or making adjustments while the engine is running can be dangerous, but it is specifically the act of leaving the operator's cab that is distinctly prohibited due to the immediate risks it entails. Emergency stop functions must also be operable when needed, highlighting the importance of maintaining control when the crane is active.