Under which condition would a "dual-point" sling load be required?

A "dual-point" sling load is required primarily for situations where loads must be stabilized to reduce sway during flight. This is crucial for maintaining control and ensuring the safety of both the load and the aircraft. Loads that are unstable can lead to excessive movement, which can adversely affect the flight dynamics, increase the risk of accidents, or cause damage to the cargo.

Using a dual-point rigging setup provides additional stability by distributing weight across two connection points, allowing for better balance and control during movement. This arrangement is particularly beneficial in dynamic environments where aerial maneuvers could alter the load's position or cause it to sway excessively.

In contrast, lighter and easier-to-transport loads typically do not require this level of stabilization, as they can often be managed effectively with single-point connections. Conditions like inclement weather may prompt other safety measures, but they do not inherently necessitate a dual-point setup. Likewise, while transporting fragile equipment does require careful handling, it can still be accomplished with a single-point sling load if appropriate precautions are taken to cushion and protect the load. Therefore, the primary justification for a dual-point sling load lies in the need for enhanced stabilization during flight.