FAA Airline Transport Pilot (ATM)Aircraft Performance and Weight and BalanceMedium
Which of the following conditions would tend to INCREASE an airplane's minimum control speed in the air (VMCA) with the critical engine inoperative?
- ACenter of gravity located further forward
- BLanding gear extended
- CCenter of gravity located further aft
- DFlaps set to the takeoff position
Show answer & explanationAnswer & explanation
Correct answer: C. Center of gravity located further aft
An aft CG shortens the moment arm between the CG and the rudder, reducing the rudder's yaw-correcting moment and requiring more airspeed for the same control authority, thus increasing VMCA. A forward CG, extended landing gear, and takeoff flaps all tend to DECREASE VMCA.
Why the other options are wrong
- A. Forward CG lengthens the rudder moment arm, decreasing VMCA.
- B. Gear extended adds keel/side area forward of the CG, decreasing VMCA.
- D. Takeoff flaps improve lift and reduce required speed, decreasing VMCA.
VMCA Factors
Minimum control speed in the air with the critical engine inoperative is affected by CG location, gear, and flap position.
- Aft CG increases VMCA
- Forward CG decreases VMCA
- Gear down and takeoff flaps decrease VMCA
Memory trick: Aft CG = short arm = need more speed to swing the rudder.