Why did Dr. Das have trouble establishing on the localizer for 28R? He followed his vector to the localizer but started to veer right of the signal when he neared the field. The localizer signal would have been Some panels are equiped with a "reverse" switch between the radio navigator and the VOR or HSI instrument. The reverse switch transforms the signal from the VHF navigation receiver so that indicator needles appear as they would in a forward approach and the pilot wouldn't have to translate (or reverse interpret) the needle. So, if equiped with a reverse switch and the switch was inadvertently in the reverse position, veering right on the localizer would look like the correct action for the pilot to make. He also may have been thinking more about circling around to runway 23 and that's why he veered right early. Though he was reminded plenty of times of what he approach was. The controller reported Dr. Das was veering right of the track. The pilot acknowledge i...