Which statement best describes the effect of bank angle on stall speed in a turning flight?

• A. The Load Factor Remains Constant In All Bank Angles.
• B. Load Factor Decreases With Bank Angle.
• C. In A Banked Turn, The Load Factor Increases With Bank Angle, Requiring Higher Airspeed To Avoid Stall; This Lowers Stall Speed Margin.
• D. Stall Speed Is Unaffected By Bank Angle.

Answer: (C)

When you bank, the wings must supply not only enough lift to support weight but also to provide the centripetal force for the turn. That means the lift needed rises, so the load factor n = L/W increases with bank angle (n = 1/cos(bank angle)). As bank angle grows, cos(bank) gets smaller and n gets larger. Since stall speed in a level turn rises with load factor (Vs in a turn is Vs straight times sqrt(n)), the airplane needs higher airspeed to avoid stalling. With a higher required speed, the margin to stall at a given actual speed decreases as the bank angle increases. So the statement that the load factor increases with bank angle, requiring higher airspeed to avoid stall and thus lowering the stall speed margin, is the correct description.