Patent ID: 7941250

Claim:
A method of obtaining a predictive vertical speed v AP of a rotorcraft, wherein the following steps are performed in succession: measuring an instantaneous vertical speed v of a rotorcraft using a vertical speed indicator connected to the rotorcraft; measuring an instantaneous proper airspeed of the rotorcraft using at least one of an omnidirectional air data system in communication with the rotorcraft, an airspeed indicator connected to the rotorcraft, and a global positioning system in communication with the rotorcraft; determining a corrective vertical speed v CORR depending on a predictive term C P1 ; and adding the corrective vertical speed v CORR to the instantaneous vertical speed v to obtain a predictive vertical speed v AP of the rotorcraft; and wherein said predictive term C P1 is determined as follows: C P ⁢ ⁢ 1 = ( v + k ) ⁢ V PP - V P 2 ⁢ ⁢ V Y - V PP where: V P =the instantaneous proper airspeed of the rotorcraft; V PP =the predictive proper airspeed of the rotorcraft as determined using the following formula where t and Δt designate respectively time and a time interval: V PP = V P + ⅆ V P ⅆ t ⁢ Δ ⁢ ⁢ t V Y =the minimum-power speed of the rotorcraft which is dependent upon a given type of the rotorcraft; and k=a predetermined characteristic constant of the rotorcraft, determined from a linear approximation that corresponds to a proportionality ratio between powers and vertical speed of the rotorcraft.