Abstract: A method of optimizing the performance of a rotary wing aircraft having at least one turbine engine with a gas generator and a turbine assembly comprising at least one turbine. In a definition step (STP1), first and second performance levels are defined for the aircraft. During a health check step (STP2), a first power margin is determined as a function of a speed of rotation of said gas generator and a second power margin is determined as a function of a temperature in said turbine assembly. During an evaluation step (STP3), each power margin is compared with a first threshold in order to determine whether a target performance level is equal to the first performance level or to the second performance level. During a display step (STP4), the target performance level is displayed.

Abstract: An aircraft power plant (2) having at least two engines (3, 4), each co-operating with respective control means (5) including respective memories (6), each memory (6) containing information for causing said engine (3, 4) to operate with a plurality of distinct utilization envelopes at iso-damage. Said power plant (2) includes determination means (10) for determining a first utilization envelope (101) for application during a takeoff stage of flight and a second utilization envelope (102) for application during a cruising stage of flight following the takeoff stage of flight, and a third utilization envelope (103) for application during a landing stage of flight following the cruising stage of flight.

Abstract: A method of providing a volume-mass law for determination of a fuel flow rate of an engine, particularly providing a fuel flow rate to a helicopter turbine, comprising the steps of: determining a sample type of fuel and a start density ?o of said sample type of fuel in said fuel tank using an equation ?0=aT+b0, with a and b0 being known for said sample type of fuel and calculating real time offset parameters bn from an algorithm to determine real time densities ? of the fuel.