How is fuel imbalance detected and corrected in flight on a narrowbody?

• A. The balance is automatically managed by gravity without pilot input.
• B. The fuel management system detects imbalance; pilots transfer fuel via crossfeed to re-establish balance within limits.
• C. There is no crossfeed capability on narrowbodies.
• D. The crew manually monitors fuel and adjusts the navigation fuel indicator only.

Answer: (B)

Fuel imbalance is sensed by the airplane’s fuel management system, which continually measures the amounts in the left and right wing tanks (and sometimes center tanks) and compares them. When the difference becomes excessive, an imbalance alert is shown and the crew is guided to take corrective action.

The standard correction is using the crossfeed system. Opening the crossfeed valve allows fuel to flow from the heavier wing to the lighter wing, transferring fuel through the aircraft’s fuel lines to restore balance. This transfer is done deliberately and monitored carefully so the tanks come back within the allowable limits and the airplane’s center of gravity stays within safe margins for safe flight handling.

This approach is typical on narrowbody airplanes, and it relies on the crew actively managing the transfer rather than letting gravity or a lack of crossfeed handle it automatically. Monitoring fuel quantities and the imbalance alert remains essential until balance is reestablished.