FAA Private Pilot Helicopter (PRH)Helicopter Aerodynamics and SystemsMedium
A pilot is preparing to transport a bulky external sling load beneath the helicopter. Which statement best describes the primary aerodynamic/handling concern associated with carrying an external load?
- AThe load has no effect on helicopter handling as long as gross weight limits are not exceeded
- BThe load can shift the center of gravity and, if it swings or oscillates, can induce pitch, roll, or yaw instability
- CExternal loads primarily affect only engine cooling, not flight control response
- DExternal loads always improve stability by lowering the center of gravity
Show answer & explanationAnswer & explanation
Correct answer: B. The load can shift the center of gravity and, if it swings or oscillates, can induce pitch, roll, or yaw instability
A slung load changes the helicopter's effective CG and adds a pendulum effect below the aircraft; if the load begins to oscillate or swing, it can couple with the helicopter's own motion and cause dangerous pitch, roll, or yaw instability.
Why the other options are wrong
- A. Weight limits alone do not account for CG shift and load dynamics.
- C. External loads primarily affect flight dynamics and CG, not engine cooling.
- D. A lower CG can help stability in some cases, but swinging loads often degrade it rather than always improving it.
External (Sling) Load Effects
An external load carried beneath a helicopter shifts the effective center of gravity and can introduce pendulum-like oscillations that couple with helicopter motion, potentially causing instability.
- Load acts like a pendulum suspended below the aircraft
- Swinging/oscillating loads can induce dangerous pitch/roll/yaw coupling
- CG location changes with load position and weight
- Pilots must monitor load behavior and limit airspeed/maneuvering accordingly
Memory trick: A swinging load is a pendulum trying to steer your helicopter.