Architecture for a hydraulic system for operating aircraft landing gear

An architecture for a hydraulic system for operating landing gear of an aircraft that includes at least one source of hydraulic pressure and at least one hydraulic return, the hydraulic system for operating the landing gear comprising actuators for operating undercarriages, which actuators are connected to a hydraulic circuit comprising a first hydraulic line that, when pressurized, causes the undercarriages to be lowered, and a second hydraulic line that, when pressurized, causes the undercarriages to be raised, said lines being pressurized selectively by means of a hydraulic distribution member comprising at least one isolation valve for selectively isolating the hydraulic circuit from the pressure source of the aircraft, and at least one selector for putting one of the lines into communication with pressure and the other line in communication with return;

• the architecture including forced return connection means for forcing the isolation valve to isolate the pressure circuit of the aircraft and to connect to return an admission line that extends between the isolation valve and the selector, and that normally conveys the pressure of the aircraft.