What is EFOB on Airbus A320? (Estimated Fuel On Board)

The Estimated Fuel On Board (EFOB) is a crucial parameter for aircraft operations and fuel management. It refers to the estimated quantity of fuel remaining on an Airbus A320 aircraft at any given moment during a flight. The EFOB is continuously calculated by the aircraft’s onboard systems and is essential for flight planning, fuel efficiency, and decision-making by pilots and dispatchers.

The EFOB is represented in kilograms (kg) or pounds (lbs). It takes into account various factors such as fuel burn rate, aircraft weight, altitude, speed, wind conditions, and payload. By constantly monitoring the EFOB, pilots can make informed decisions and take necessary actions to ensure sufficient fuel for the entire flight, including contingencies.

The accurate estimation of the EFOB is critical for safety and efficiency. Insufficient fuel can lead to fuel exhaustion, which is a serious flight hazard. Excess fuel, on the other hand, adds unnecessary weight and increases operational costs. Therefore, understanding the EFOB and its implications is vital for aviation professionals involved in flight planning and operations.

Calculating Estimated Fuel On Board

The EFOB is derived through a combination of pre-flight calculations and continuous monitoring during the flight. Before departure, the aircraft’s dispatchers consider various variables and use performance planning software to determine the initial fuel load. These variables include the planned route, weather conditions, expected delays, alternate airports, and regulatory requirements.

During the flight, the EFOB is recalculated using real-time data and updates. The Flight Management System (FMS) plays a crucial role in this process. It continuously monitors the aircraft’s fuel flow, taking into account engine performance, wind data, altitude, and aircraft weight. The FMS also considers any changes to the flight plan, such as route modifications or unexpected weather conditions.

The EFOB calculation becomes more accurate as the flight progresses because the system can adjust parameters based on actual fuel burn rates. Pilots also have the ability to manually input data, such as new wind information, to further refine the EFOB calculation. This flexibility ensures that the flight crew has the most up-to-date and accurate information regarding fuel on board.

Importance of Estimated Fuel On Board

The EFOB is a critical factor in flight planning and decision-making. Airlines strive to optimize fuel consumption without compromising safety. By accurately estimating the EFOB, airlines can determine the most efficient cruising altitudes, speeds, and routes for their aircraft. This optimization reduces fuel consumption, lowers operational costs, and minimizes environmental impact by reducing carbon emissions.

Additionally, the EFOB is essential for safety-related decisions. Pilots use the EFOB to determine if they have sufficient fuel to reach their destination, considering all possible contingencies, such as diverting to an alternate airport or enduring unexpected delays. The EFOB allows pilots to identify critical points in the flight where refueling may be necessary or where alternate plans need to be made.

Moreover, the EFOB is vital for operational efficiency and cost management. Airlines closely monitor fuel consumption and aim to minimize fuel uplift, which is the additional fuel loaded beyond the minimum required for a flight. By accurately estimating the EFOB, airlines can plan their fuel uplifts more effectively, preventing excessive fuel load and reducing the associated costs.


The Estimated Fuel On Board (EFOB) is a crucial parameter for flight planning, fuel management, and decision-making on the Airbus A320 aircraft. It enables pilots and dispatchers to estimate the remaining fuel on board during a flight, considering factors such as fuel burn rate, weight, speed, wind, and payload. The EFOB is continuously monitored and recalculated using real-time data, ensuring accurate information for optimizing efficiency and safety.

Understanding the EFOB’s importance and implications is vital for aviation professionals involved in flight operations. Accurately estimating the EFOB allows airlines to optimize fuel consumption, reduce operational costs, and minimize environmental impact. It also enables pilots to make informed decisions regarding contingencies and ensures operational efficiency and cost management. The EFOB is a critical tool that enhances safety and performance on the Airbus A320 and other aircraft.

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