Abstract: Aircraft fuel tank, which has a visual control system inside the tank, includes at least a side wall (12), an upper wall (14) and a lower wall (16), the tank (10) comprising a visual inspection system (22) inside the tank (10). The visual inspection system (22) includes an inspection eyepiece (24) arranged in one of the walls (12, 14, 16), a light inlet (26) arranged in one of the walls (12, 14, 16) and configured to allow light from an artificial light source (30) situated outside the tank (10) to enter the tank (10), and a light guide (28) protruding inside the tank (10) from the light inlet (26) to guide the light produced by the artificial light source (30) to the inside of the tank (10).