the -510s had a Smiths autopilot
That's right - my main function during an automatic approach and landing was to carefully set up the kit before engaging a large switch on the center pedestal. It was labelled "Prime Land" and if all was well it locked magnetically. As the system was single channel I then had to monitor and call out any deviations which would result in a go-around - the most exciting bit being the autopilot disengage light coming on after DH when I would yell "LAND MANUAL" usually followed by a huge thump on the runway!!