During approach in landing configuration, what does a positive stall margin indicate?

• A. The stall speed is higher than approach speed.
• B. The aircraft cannot maintain altitude.
• C. The margin is zero.
• D. The approach speed exceeds stall speed, giving a positive margin.

Answer: (D)

A positive stall margin means there is a safety buffer between the speed required to fly (approach speed) and the speed at which the wing would stall (stall speed) in landing configuration. When the approach speed is higher than the stall speed, you have extra lift reserve and control authority, which helps you stay out of the stall even with gusts or small pilot inputs. That’s why the correct statement is that the approach speed exceeds stall speed, giving a positive margin. If stall speed were higher than approach speed, you’d have a negative margin and could stall; if the margin were zero, you’d be right at stall with no buffer. The idea that you “cannot maintain altitude” isn’t a direct definition of margin.