Which statement is true when comparing pressure-based total fuel at full versus gravity-based total fuel at full?

Which statement is true when comparing pressure-based total fuel at full versus gravity-based total fuel at full?

• A. Pressure-based total fuel at full is higher than gravity-based total fuel at full
• B. Gravity-based total fuel at full is higher than pressure-based total fuel at full
• C. They are equal
• D. Not comparable

Answer: (A)

The important idea here is how fuel quantity is derived from two independent measurements: a pressure-based method that uses hydrostatic pressure in the tank to infer volume, and a gravity-based method that converts fuel weight to volume using density. When tanks are full, the pressure-based indication responds to the maximum hydrostatic head, and with typical fuel temperature effects and calibration, it tends to yield a higher volume estimate than the weight-based calculation. The gravity-based approach relies on actual weight and a density value, which can be lower if the fuel is warm (density drops) or affected by calibration tolerances, leading to a lower indicated quantity. So, at full, the pressure-based total fuel is usually higher than the gravity-based total fuel.

The important idea here is how fuel quantity is derived from two independent measurements: a pressure-based method that uses hydrostatic pressure in the tank to infer volume, and a gravity-based method that converts fuel weight to volume using density. When tanks are full, the pressure-based indication responds to the maximum hydrostatic head, and with typical fuel temperature effects and calibration, it tends to yield a higher volume estimate than the weight-based calculation. The gravity-based approach relies on actual weight and a density value, which can be lower if the fuel is warm (density drops) or affected by calibration tolerances, leading to a lower indicated quantity. So, at full, the pressure-based total fuel is usually higher than the gravity-based total fuel.