What condition triggers the transfer valves to engage in the fuel balancing system?

The fuel balancing system is designed to ensure that the aircraft maintains an optimal fuel distribution during flight. The transfer valves engage to correct any significant fuel imbalance between the tanks. A fuel imbalance greater than 20 lbs sustained for 30 seconds is typically the threshold that triggers this response in the system.

When the fuel difference exceeds this specific limit and persists for the set duration, it indicates a serious imbalance that could affect the aircraft's performance and handling. By activating the transfer valves, the system redistributes fuel to stabilize the center of gravity and overall aircraft balance. This proactive measure helps to ensure safety and efficiency in flight operations.

In contrast, the conditions related to fuel pressure or lesser imbalances may not indicate a need for immediate corrective action. Thresholds set at 10 lbs for 15 seconds or lower fuel pressures do not necessitate the same urgent response as the greater imbalance registered over 30 seconds, reflecting the system's prioritization of larger discrepancies that could significantly impact performance.