Patent ID: 8240615

Claim:
A method for automatically protecting an aircraft against a hard landing, comprising the steps of: a) measuring, by a measuring unit, current vertical speed and current relative height of the aircraft with respect to the ground; b) generating, by a first command generating unit, first commands for controlling control surfaces to act on the vertical speed of the aircraft, wherein the first commands are generated by determining an intermediate command from said measured current vertical speed and said current height, and converting the intermediate command into turn angles for said control surfaces; and c) applying, by a speed calculation unit, said first commands, which represent protection commands, to said control surfaces, wherein said first commands are generated from said measured current vertical speed and said measured current height of the aircraft, and speed information that takes into account a predetermined reference vertical speed in which the aircraft touches down on the ground at a vertical speed not greater than the predetermined reference vertical speed such that there is no hard landing, wherein the intermediate command is determined from a value that is: a) vertical acceleration value γz, which is determined using the following expression: γ z =( Vz 2 −V cons 2 )/(2 h ) in which: Vz is said measured current vertical speed of the aircraft; Vcons is said speed information which corresponds to said reference vertical speed; and h is said measured current height, or b) a value that is proportional to the difference between the measured current vertical speed and a vertical speed value that corresponds to the vertical speed of a speed profile at said measured current height, and said speed profile corresponds to said speed information and represents a variation in a limit value of vertical speed as a function of height relative to the ground, wherein the limit value of vertical speed is equal to said reference vertical speed at zero height.