Appendix 1 These areas include, but are not limited to, the cockpit, passenger compartments, galleys, and all classes of cargo and baggage compartments.
f. Zero Fuel Weight. Typically, transport category airplanes are designed to carry the fuel supply in the wings. In addition to any other advantages, locating the fuel in the wings relieves wing bending stresses and allows a higher maximum weight than would be possible with the same quantity of fuel located within the fuselage. For such airplanes, zero fuel weight is established as a limit to ensure that maximum wing bending stresses are not exceeded by replacing fuel in the wings with an equal weight of payload carried in the fuselage. When an auxiliary fuel tank is installed within the fuselage, the existing zero fuel weight limit is no longer directly applicable because the fuel contained in that tank does not relieve wing bending stresses. It 1s, therefore, necessary to reduce the zero fuel weight limit by the maximum usable fuel capacity of the auxiliary tank. Alternatively, the zero fuel weight limit may be redefined as the maximum zero wing fuel weight limit. Any fuel contained in the auxiliary tank would then be treated as payload from a weight and balance standpoint.
the limit and its meaning.
Par 1 3 (and 4) * U. S. GOVERNMENT PRINTING OFFICE: 1986 491-828/54716