When should the crane operator immediately stop operations?

The scenario where the operating envelope is penetrated is critical because it directly relates to maintaining safe operational boundaries for the crane. The operating envelope refers to the predetermined limits within which the crane can safely operate, including its reach, load capacity, and height restrictions. If this envelope is breached, it significantly increases the risk of accidents, such as tipping, load drops, or collisions with nearby objects or personnel.

When the operating envelope is violated, the crane may be subjected to forces and conditions that exceed its design specifications. This situation can compromise the structural integrity of the equipment, increasing the likelihood of failure. Therefore, the immediate cessation of operations in this scenario is essential to maintain safety for the operator, the equipment, and anyone in proximity to the crane.

The other situations, while important, do not necessitate an immediate stop as clearly as penetrating the operating envelope. Losing sight of the load may lead to unsafe practices, fatigue can reduce performance but might not warrant an immediate stop if managed, and sudden weather changes should indeed prompt caution, but do not always require halting operations right away unless they directly affect the stability and safety parameters of the lift.