Jason D Capps

US Patent:

51385597, Aug 11, 1992

Filed:

Aug 28, 1989

Appl. No.:

7/399601

Inventors:

Johannes W. Kuehl - Edmonds WA
Jason W. Capps - Bellevue WA

Assignee:

The Boeing Company - Seattle WA

International Classification:

G01F 2300
G08B 2100

US Classification:

364509

Abstract:

A method and system for measuring the mass quantity and volume of fuel in an aircraft fuel tank is disclosed. A pressure assembly (124) is disposed proximate the lowest portion of each fuel tank on an aircraft (60), with respect to a wing tank (100). The pressure sensor assembly includes a temperature probe (126) having a plurality of temperature sensors (128) mounted therein at spaced apart elevations within the fuel tank. Also included is an attitude sensor (150) in which are provided a roll sensor (156) and a pitch sensor (160) for respectively determining the roll and pitch angles of the fuel surface with respect to a vertical reference axis on the aircraft. The reference axis is aligned with an acceleration-sensitive axis of an accelerometer (164), which is operative to determine the acceleration acting upon fuel within the wing tank, and using the roll and pitch angles, the acceleration normal to the upper surface of the fuel. Wing bending sensors (82) are installed in each wing to determine the deflection of the wing as a result of loading the wing tanks with fuel and as a result of in-flight aerodynamic forces on the wing. The signals from each of these sensors are input to a microprocessor (178), which determines the height of fuel in each tank, corrects for variations in density due to temperature stratification, determines the volume and mass of fuel as a function of fuel height, correcting for the attitude of the fuel tank and for acceleration applied to the mass of fuel during measurement of its pressure at the bottom of each fuel tank.