What are common causes of load swing during sling-load operations?

• A. Strong tailwinds and rotor wash
• B. Cold weather and icing
• C. High altitude and fuel load
• D. Gusts, rapid maneuvers, and throttle changes

Answer: (D)

Load swing happens because the suspended load behaves like a pendulum and responds to abrupt changes in lift, airspeed, and external forces. The most common causes are gusts, rapid maneuvers, and throttle changes. Gusts deliver sudden side-to-side or fore-aft pushes on the load, setting it swinging. Quick turns, climbs, or descents alter the helicopter’s attitude and rotor wash, which pulls on the line and causes the load to swing as it lags behind the helicopter’s motion. Changes in throttle or collective alter rotor thrust and power, producing a quick shift in lift that translates into a jerk or oscillation of the load. While environmental factors like wind or rotor wash can influence the load, these transient disturbances and power changes are the primary drivers of load swing.