What is the purpose of the flap load relief system on large aircraft?

• A. To prevent over-stressing of trailing edge flaps
• B. To increase flap lift
• C. To reduce drag during takeoff
• D. To assist flap retraction speed

Answer: (A)

When flaps are extended on large airplanes, the wing and flap structure experience high aerodynamic loads that can push them toward their design limits. A flap load relief system is there to protect against that by automatically lightening the load on the flaps when those loads get too high. It senses excessive load or deflection and allows the flap to move toward a less loaded condition, reducing the bending moment on the flap and wing. This prevents overstress and fatigue, keeping the structure safe during gusts, high-l lift phases, or aggressive maneuvers. It isn’t about increasing lift, cutting drag during takeoff, or speeding up flap retraction; its job is structural protection by relieving flap loads.