On the Ground
Loads on the ground are taken up by the undercarriage and then transmitted to the aircraft main structure. Landing-gear loads depend on the specification of Vstall, the maximum allowable sink speed rate at landing, and the MTOM. This is addressed in greater detail in Chapter 7, which discusses undercarriage layout for conceptual study.
5.4.1 In Flight
In-flight loading in the pitch plane is the main issue considered in this chapter. The aircraft structure must be strong enough at every point to withstand the pressure field around the aircraft, along with the inertial loads generated by flight maneuvers. The V-n diagram is the standard way to represent the most severe flight loads that occur in the pitch plane (i. e., X-Z plane), which is explained in detail in Section 5.7. The load in other planes is not discussed herein.