Abstract: Its object is to allow measurement of the volume of fuel (2) using optic fiber cables (3); it is characterized in that, adhered to one or more of the inner faces of the tank (1) there is at least one sheet (4) in which a plurality of optic fiber cables (3) with different lengths are included, located between the inner face of the tank and the sheet (4). One set of the ends (10) of the optic fiber cables (3) are disposed so that they are in contact with the fuel (2) when it reaches their level, thereby allowing measurement of the fuel level at all times. The preferred embodiment distributes the optic fiber cables (3) on two opposing lateral faces of the tank (1) so that they cross over one another and in opposite directions to measure any fuel level. It is applied in aeronautics.

Abstract: Provided herein are drainage valves for removing water accumulated in the lower part of fuel tanks of an aircraft. The valves can be affixed in correspondence with a lower skin forming part of the tanks. The lower skin includes recesses for the complementary housing of the heads of the valves that, in combination with some axial fastening nuts, immobilize the valves to that skin. The recesses can comprise a conical structure obtained by deformation of the lower skin, and with the deformation an inner elevated seat is further obtained, on which seat the axial fastening nuts press, maintaining the thickness of the skin in the area where the valves are located, thus preventing the area from weakening as it happens conventionally.

Abstract: Its object is to allow measurement of the volume of fuel (2) using optic fibre cables (3); it is characterized in that, adhered to one or more of the inner faces of the tank (1) there is at least one sheet (4) in which a plurality of optic fibre cables (3) with different lengths are included, located between the inner face of the tank and the sheet (4). One set of the ends (10) of the optic fibre cables (3) are disposed so that they are in contact with the fuel (2) when it reaches their level, thereby allowing measurement of the fuel level at all times. The preferred embodiment distributes the optic fibre cables (3) on two opposing lateral faces of the tank (1) so that they cross over one another and in opposite directions to measure any fuel level. It is applied in aeronautics.

Abstract: The drainage valves have the purpose of removing the water accumulated in the lower part of fuel tanks of an aircraft, said valves being affix in correspondence with a lower skin forming part of said tanks. The lower skin includes recesses for the complementary housing of the heads of the valves that, in combination with some axial fastening nuts, immobilize the said valves to that skin. It is characterized in that the recesses comprise a conical structure obtained by deformation of the lower skin, and with said deformation an inner elevated seat is further obtained, on which seat the axial fastening nuts press, maintaining the thickness of the skin in the area where the valves are located, thus preventing the said area from weakening as it happens conventionally.