EFIS (Electronic Flight Information System) displays are screens that are in front of the pilots and generally include the Primary Flight Display (PFD) and Navigation Display (ND). The EFIS PFD displays primary flight indications to the pilots including speed, pitch, rate of climb, altitude, autopilot modes etc. The Navigation Display (also referred to as an HSI - Horizontal Situation Indicator) displays a top-down navigation display showing the location of the aircraft with respect to navigation fixes or radio aids, and also indicates heading, track, wind velocity etc.