On failure, a burst rotor of a wing-mounted engine (13, 23) can penetrate fuel tank walls in the wing of a conventional aircraft. There exists a zone that is at risk of such damage. Thus, the layout of fuel tanks (3, 11C, 21C) in the wing of an aircraft in accordance with embodiments includes port and starboard inner fuel tanks (11C, 21C) that are positioned adjacent to a central fuel tank (3) in the central wing section, but outside of the at-risk zone. Each of the port and starboard inner fuel tanks (11C, 21C) is defined in part by a respective inner boundary member (5RP, 5RS) that when viewed in plan extends, at least in part, in a direction at an angle of less than 20.degree. to the adjacent vertical plane (A-A) defining the at-risk zone. Thus the amount of fuel stored in fuel tanks (11C, 21C) in the wing assembly that cover a region outside of the at-risk zone and that do not extend into the at-risk zone may be increased.