On August 10, 1968, Piedmont Airlines Flight 230 was on an ILS localizer-only approach to runway 23 when it struck trees 360 feet from the runway threshold. The aircraft continued and struck up-sloping terrain short of the runway in a nose down attitude. The aircraft continued up the hill and onto the airport, coming to rest 6 feet beyond the threshold and 50 feet from the right edge of the runway. A layer of dense fog was obscuring the runway threshold and about half of the approach lights. Visual conditions existed outside the fog area. All three crew members and thirty-two of the thirty-four passengers perished. The National Transportation Safety Board blamed the accident on an "unrecognized loss of altitude orientation during the final portion of an approach into shallow, dense fog." The disorientation was caused by a rapid reduction in the ground guidance segment available to the pilot at a point beyond which a go-around could be successfully effected.