Means for controlling the vertical path of an aircraft

Claim 1

Apparatus for sequentially controlling the vertical flight path of an aircraft through the stages of descent, flare out, and touchdown, comprising: a plurality of adjustable spoilers, mounted at the upper surface of the wings of said aircraft for selectively controlling the lifT thereof; a hydraulic actuator connected to each of said spoilers for raising, lowering, and holding said spoilers in a selected position; means normally biasing each of said spoilers to a position approximately midway through its range of adjustment in response to the activation of said flight control apparatus at the commencement of said descent stage; a pump for supplying hydraulic fluid under pressure to said actuators; a servo valve, adapted to be electrically actuated in response to servocontrol signals, connected in series with said pump and a hydraulic reservoir to said actuators to control the position of said actuators and said spoilers; a glide-slope receiver responsive to a ground-based radio transmitter to produce glide-slope position signals which are a measure of the vertical displacement above and below the predetermined radio glide path generated by said transmitter; an altitude sensor for producing altitude signals indicative of the altitude of said aircraft above the surface of the earth; computer means having first and second inputs connected to said glide-slope receiver and to said altitude sensor, respectively, and having an output connected to said servo valve, said computer being responsive to the combination of said glideslope position signals and said altitude signals, it being primarily responsive to said glide-slope position signals during said descent stage when said aircraft is above a given altitude and thereafter primarily responsive to said altitude signals during said flare out and touchdown stages when said aircraft is below said given altitude, for generating said servocontrol signals for said servo valve, whereby the lift of said wings is continuously controlled by the output of said computer means through said descent, flare out, and touchdown stages.