Like the Second Heart and Netwatch Netdriver MK.5, The “Falcon” is located at the same Ripper Doc named “Doc Ryder” on the western half of Heywood.
Fast Travel to the Pumping Station waypoint on your map, and you’ll notice a Ripper Doc located directly across the street from you. Head across the street, up the stairs, and you’ll notice (in massive glowing words) “DOC RYDER.” Remember this Ripper Doc, because he sells probably the most valuable Cyberware you can acquire in Cyberpunk 2077, and you’ll definitely want to return when you save up some more cash!
Once you head inside the Ripper Doc’s shop and have spoken with Doc Ryder himself, you just need to navigate to your Operating System Cyberware tab, and there you will find the Militech “Falcon” Sandevistan MK.5, just ready to be plucked.