What is the maximum allowable fuel imbalance between tanks for takeoff?

The maximum allowable fuel imbalance between tanks for takeoff in the ERJ 170/175 is set to ensure optimal aircraft performance and safety. An imbalance of up to 800 pounds is acceptable to maintain proper weight distribution and center of gravity, which are critical for stable flight characteristics, particularly during takeoff and initial climb.

Keeping fuel balanced helps in managing aerodynamic efficiency and ensures that the aircraft's handling characteristics remain predictable. Exceeding this limitation might introduce undesirable handling effects and could affect the aircraft's performance during critical phases of flight, such as takeoff.

While values such as 500 lbs, 700 lbs, and 1000 lbs reflect important tolerances for fuel balance, they fall outside the specified maximum allowable limit for takeoff weight distribution in the ERJ 170/175. Therefore, an 800-pound imbalance is the accepted threshold that allows for safe operation under normal conditions.