INADEQUATE VISUAL LOOKOUT BY THE PILOTS OF BOTH AIRPLANES, WHICH RESULTED IN THEIR FAILURE TO SEE-AND-AVOID CONFLICTING TRAFFIC, AND FAILURE OF THE RELIEVING CONTROLLERS TO USE THE RADAR DISPLAY TO IDENTIFY AND SEQUENCE AN AIRPLANE ENTERING THE PATTERN. FACTORS RELATED TO THE ACCIDENT WERE: AN INADEQUATE BRIEFING BY THE OFF-GOING CONTROLLER, AND INACCURATE POSITION REPORTS BY THE PILOT-IN-COMMAND OF N5279R.