What is the maximum allowable fuel imbalance for takeoff?

• A. 300 pounds
• B. 400 pounds
• C. 500 pounds
• D. 600 pounds

Answer: (A)

Fuel balance is about avoiding a sideways, or yawing, moment on the aircraft. When fuel isn’t evenly distributed between the left and right tanks, one wing is heavier, which tends to push the nose away from that side. For takeoff, you must be able to control the aircraft if an engine fails. The airplane’s rudder and overall controllability have limits, and the fuel balance limit is set to keep that yaw moment within what you can counter with normal control inputs.

For this airplane, the maximum allowable imbalance is 300 pounds. Staying at or below this limit ensures that, even with an engine inoperative, you have enough rudder authority and stability to maintain a safe takeoff path and climb. If the imbalance exceeds that amount, you’d need to equalize the fuel load before takeoff (or delay the takeoff) to restore controllability.