A system for simultaneously pumping and measuring density of an aircraft fuel, the system comprising: a centrifugal pump including an impeller configured to pump the aircraft fuel; a speed sensing arrangement configured to determine a rotational frequency of the impeller while the centrifugal pump is pumping the aircraft fuel, the speed sensing arrangement comprising: a tachometer configured to measure a rotational velocity of the impeller, the rotational velocity being indicative of the rotational frequency of the aircraft fuel; a flow-rate sensing arrangement configured to measure flow rate of the aircraft fuel through the centrifugal pump; a pressure sensing arrangement configured to measure pressure at two different points within or across the centrifugal pump or a differential pressure between the two different points while the centrifugal pump is pumping the aircraft fuel; one or more processors ; and computer-readable memory containing data indicative of an empirically-determined head-curve relation corresponding to the centrifugal pump and determined during a characterization phase, the head-curve relation defining a relation between density of the aircraft fuel and flow rate, speed, and either the pressures of the two different points or the differential pressure between the two different points, the computer-readable memory further containing instructions that, when executed by the one or more processors, cause the system to: calculate, using the empirically-determined head-curve relation during an operation phase, a density of the aircraft fuel based on the rotational frequency, the flow rate, and either the pressures of the two different points or the differential pressure between the two different points. a centrifugal pump including an impeller configured to pump the aircraft fuel; a speed sensing arrangement configured to determine a rotational frequency of the impeller while the centrifugal pump is pumping the aircraft fuel, the speed sensing arrangement comprising: a tachometer configured to measure a rotational velocity of the impeller, the rotational velocity being indicative of the rotational frequency of the aircraft fuel; a flow-rate sensing arrangement configured to measure flow rate of the aircraft fuel through the centrifugal pump; a pressure sensing arrangement configured to measure pressure at two different points within or across the centrifugal pump or a differential pressure between the two different points while the centrifugal pump is pumping the aircraft fuel; one or more processors ; and computer-readable memory containing data indicative of an empirically-determined head-curve relation corresponding to the centrifugal pump and determined during a characterization phase, the head-curve relation defining a relation between density of the aircraft fuel and flow rate, speed, and either the pressures of the two different points or the differential pressure between the two different points, the computer-readable memory further containing instructions that, when executed by the one or more processors, cause the system to: calculate, using the empirically-determined head-curve relation during an operation phase, a density of the aircraft fuel based on the rotational frequency, the flow rate, and either the pressures of the two different points or the differential pressure between the two different points. <EOS>