What must an operator do if they leave the cab of the crane while the engine is running?

When an operator leaves the cab of the crane while the engine is running, maintaining visibility of the crane is essential for several reasons. Leaving the engine running can pose various hazards, including the risk of unintended movements, accidents, or equipment damage. By keeping the crane in view, the operator can monitor its position and movement, ensuring that it remains safe and stable while they are away. This vigilance allows for immediate action in case of any unexpected issues, such as an obstruction becoming dislodged or an unauthorized individual approaching the crane.

The other choices are important aspects of crane operation, but they don't directly address the specific requirement of maintaining awareness and control when the engine is running and the operator is away. For example, switching off the engine is a good safety practice, but it is not the focus of this particular situation. Similarly, signaling other workers or performing a safety inspection are valuable actions but are not directly related to the immediate concern of managing the crane’s operation while the operator is absent.