Extending landing gear has what effect on VMC?

Extending landing gear has what effect on VMC?

• A. Extending landing gear increases VMC.
• B. Extending landing gear decreases VMC.
• C. No effect on VMC.
• D. Extending landing gear increases stall speed.

Answer: (B)

VMC is the minimum speed at which the airplane can be controlled with one engine inoperative, determined by the balance between the yawing moment from asymmetric thrust and the rudder/stability available to counter it. Extending the landing gear increases parasitic drag and generally enhances directional stability. That extra drag dampens the yaw tendency produced when one engine is out, so the rudder doesn’t have to work as hard to keep the aircraft straight. As a result, you can maintain control at a lower speed, lowering VMC. Stability and drag changes from gear down affect VMC, not stall speed, so extending the gear down tends to decrease VMC rather than increase it.

VMC is the minimum speed at which the airplane can be controlled with one engine inoperative, determined by the balance between the yawing moment from asymmetric thrust and the rudder/stability available to counter it. Extending the landing gear increases parasitic drag and generally enhances directional stability. That extra drag dampens the yaw tendency produced when one engine is out, so the rudder doesn’t have to work as hard to keep the aircraft straight. As a result, you can maintain control at a lower speed, lowering VMC.

Stability and drag changes from gear down affect VMC, not stall speed, so extending the gear down tends to decrease VMC rather than increase it.