Helicopter optical position indicator

Claim 1

An optical device for assisting the landing of helicopters and other vertical descent aircraft by providing visual information to permit the pilot to pursue a flight path along a prescribed center line relative to the landing pad, to locate the aircraft at a precise hover point along said center line and directly above the desired touchdown point, and to continuously indicate the altitude of the aircraft above the landing pad during descent comprising: a center line module having at least first and second light sources and a first lens system positioned with respect to said light sources to form respective images thereof, light baffle means situated within said center line module for separating the images of said light sources as seen by said pilot, said first light source being positioned a first distance from said first lens system wherein the image formed thereof as viewed by said pilot appears to remain stationary and serves as a vertical datum bar, said second light source being positioned at a second distance from said first lens system whereby the image formed thereof serves as a vertical center line bar, said vertical center line bar when viewed by said pilot appearing to move horizontally with respect to said vertical datum bar in response to movement in a horizontal plane on either side of said center line by said pilot, the alignment of said center line bar with said datum bar by said pilot being indicative of flight along said prescribed center line, a hover module having at least a single light source and a second lens system positioned with respect thereto such that the image formed by said second lens system as seen by said pilot serves as a vertical hover bar, hover point alignment datum arms positioned in predetermined relationship to said hover module, said hover bar appearing to said pilot to move in a horizontal direction in response to changes in the distance of said aircraft from said hover point, the concurrent alignments by said pilot of said center line bar with said datum bar and said hover bar with said hover point alignment datum arms being indicative of the aircraft having reached said hover point. a descent module having at least a single light source and a third lens system positioned with respect thereto such that the image formed by said third lens system as seen by said pilot serves as a horizontal descent bar, a hover position datum arm and a touchdown datum arm positioned at substantially opposite extremities of said descent module, alignment by said pilot of said horizontal descent bar with said hover position datum arm indicating a predetermined hover point altitude prior to descent, said descent bar appearing to move in a vertical direction toward said touchdown datum arm during descent, the alignment of said descent bar with said touchdown datum arm, together with said concurrent alignments of said center line And hover bars with their respective datum markers indicating the presence of said aircraft at said touchdown point.