1. A method of controlling subsystems of an aircraft, each subsystem having at least one member for selecting from a list comprising at least: an actuatable device that can change state on request; an actuator connected to at least one actuatable device for controlling the state of the actuatable device; a sensor measuring at least one parameter; an information interface providing at least one item of information to a person; and a control interface enabling at least one other member to be controlled; the method comprising the following steps: during a preparation step performed on the ground or in flight prior to a command sequence, storing at least one global order in a database, each global order including an eligibility condition specifying at least one condition to be satisfied in order to be able to select the global order, at least one global order including at least one activation condition, each global order specifying a command sequence including at least two actions to be implemented either in sequence or in parallel by two different members; during an initialization step of initializing a command sequence, an onboard computer determines whether a stored global order, referred to as the “selected global order”, has been selected automatically or by a action referred to as “pilot action” performed by a person; if the selected global order includes at least one activation condition, then during an activation step of activating the command sequence, an onboard computer determines the feasibility of the selected global order by verifying that the aircraft can implement the selected global order by determining whether each activation condition of the selected global order is satisfied; and during an implementation step of implementing the command sequence, if the selected global order does not have any activation condition or if each activation condition of the selected global order is satisfied, the onboard computer implements the actions specified by the selected global order.