Final answer:
Auxiliary fuel tank pumps transfer fuel to the center fuel tank when the fuel quantity in the center tank reduces below a certain level. This helps maintain balance and stability in the aircraft.
Step-by-step explanation:
The auxiliary fuel tank pumps transfer fuel to the center fuel tank when the quantity of fuel in the center tank reduces below a certain level, typically measured using fuel quantity sensors. The transfer helps to maintain balance and stability in the aircraft by redistributing fuel from the auxiliary tanks to the center tank.
For example, in the A321 aircraft, the auxiliary fuel tank pumps are activated automatically when the fuel level in the center tank drops below 453 kg. The transfer continues until either the fuel level in the center tank reaches 1075 kg or the auxiliary tanks are empty.
An auxiliary or boost pump can be used for a number of important functions, such as: 1. Priming a fuel injected engine prior to start-up. 2. Restoring fuel flow to the engine any time the engine driven pump fails or is unable to maintain adequate fuel flow.