Spoiler limitations require that spoilers must not be extended below which thresholds?

• A. 300 AGL
• B. VREF + 10
• C. Must not be extended below 300 AGL or below VREF + 10
• D. Below 400 AGL

Answer: (C)

Spoilers are speed brakes that reduce lift and add drag, so there are safety limits on when they can be used. Extending them too close to the ground or at too low an airspeed can upset control, increase sink rate, or leave you with insufficient margin to recover. The practical rule combines both a minimum altitude and a minimum speed: they must not be extended below 300 feet AGL and not below VREF plus 10 knots. This dual limit ensures you have enough altitude to manage the approach and enough airspeed to maintain control when the spoilers deploy. That’s why the option specifying both thresholds is the best answer.