What phase of flight allows a maximum fuel imbalance of 800 lbs?

The correct answer is "all other phases," as this phase of flight allows for a maximum fuel imbalance of 800 pounds. During phases of flight other than takeoff and landing, the aircraft operates under a relatively stabilized condition where a higher fuel imbalance is manageable without significantly impacting aircraft performance or safety.

Takeoff and landing require stricter fuel imbalance limitations, typically due to the need for precise control and stability during critical phases of operation. In cruise, while a slight imbalance can still be permissible, it is generally managed more closely to optimize performance and maintain the structural integrity of the aircraft.

Thus, "all other phases" accurately encapsulates various conditions prior to landing or after taking off where a maximum fuel imbalance of 800 pounds is acceptable, ensuring the aircraft remains within safe operating parameters throughout those phases.