Advisory Reiterates Attitude Display Design

The FAA issued draft Advisory Circular 25-11-1X clarifying electronic cockpit display design rules. First issued in 1987, the revised circular adds information on Class III electronic flight bags, enhanced and synthetic vision systems and electronic standby and head-up displays. Although avionics technology has advanced, the proposed circular still recommends that glideslope indicators or deviation scales “should be located to the right side of the primary attitude indication.” The NTSB final report on the Nov. 22, 2004 crash of a Gulfstream III noted that in the fleet flown by the accident pilots, five airplanes, including the accident GIII, had the glideslope indicator on the left side and three had the indicator on the right side. The Safety Board believes that the pilots mistook the right-side fast/slow indicator for the glideslope.