A method of monitoring status of an energy reserve accumulator, connected to a fluid system, includes the following successive operations once the fluid system has stabilized for pressure: measuring a first time taken by the fluid system to progress from a predetermined first pressure to a predetermined second pressure, lower than the predetermined first pressure; measuring a second time taken by the system to progress from a predetermined third pressure, lower than the predetermined second pressure, to a predetermined fourth pressure, lower than the predetermined third pressure; and comparing the first and second times to determine the status of the energy reserve accumulator. Such a method may find use for example in an aircraft.